Electric locomotives are quiet compared to diesel locomotives since there is no engine and exhaust noise and less mechanical noise. The lack of reciprocating parts means electric locomotives are easier on the track, reducing track maintenance. Power plant capacity is far greater than any individual locomotive uses, so electric locomotives can have a higher power output than diesel locomotives and they can produce even higher short-term surge power for fast acceleration. Electric locomotives are ideal for commuter rail service with frequent stops. They are used on high-speed lines, such as ICE in Germany, Acela in the U.S., Shinkansen in Japan, China Railway High-speed in China and TGV in France. Electric locomotives are used on freight routes with consistently high traffic volumes, or in areas with advanced rail networks.

Electric locomotives benefit from the high efficiency of electric motors, often above 90% (not including the inefficiency of generating the electricity). Additional efficiency can be gained from regenerative braking, which allows kinetic energy to be recovered during braking to put power back on the line. Newer electric locomotives use AC motor-inverter drive systems that provide for regenerative braking.

The chief disadvantage of electrification is the cost for infrastructure: overhead lines or third rail, substations, and control systems. Public policy in the U.S. interferes with electrification: higher property taxes are imposed on privately owned rail facilities if they are electrified.[citation needed] The EPA regulates exhaust emissions on locomotive and marine engines, similar to regulations on car & freight truck emissions, in order to limit the amount of carbon monoxide, unburnt hydrocarbons, nitric oxides, and soot output from these mobile power sources.[2] In Europe and elsewhere, railway networks are considered part of the national transport infrastructure, just like roads, highways and waterways, so are often financed by the state. Operators of the rolling stock pay fees according to rail use. This makes possible the large investments required for the technically and, in the long-term, also economically advantageous electrification. Because railroad infrastructure is privately owned in the U.S., railroads are unwilling to make the necessary investments for electrification.

Electric locomotive of the Baltimore Belt Line, 1895: The steam locomotive was not detached for passage through the tunnel. The overhead conductor was a ∩ section bar at the highest point in the roof, so a flexible, flat pantograph was used

The first known electric locomotive was built in 1837 by chemist Robert Davidson of Aberdeen, and it was powered by galvanic cells (batteries). Davidson later built a larger locomotive named Galvani, exhibited at the Royal Scottish Society of Arts Exhibition in 1841. The seven-ton vehicle had two direct-drivereluctance motors, with fixed electromagnets acting on iron bars attached to a wooden cylinder on each axle, and simple commutators. It hauled a load of six tons at four miles per hour (6 kilometers per hour) for a distance of one and a half miles (2 kilometers). It was tested on the Edinburgh and Glasgow Railway in September of the following year, but the limited power from batteries prevented its general use. It was destroyed by railway workers, who saw it as a threat to their job security.[3][4][5]

The first electric passenger train was presented by Werner von Siemens at Berlin in 1879. The locomotive was driven by a 2.2 kW, series-wound motor, and the train, consisting of the locomotive and three cars, reached a speed of 13 km/h. During four months, the train carried 90,000 passengers on a 300-metre-long (984 feet) circular track. The electricity (150 V DC) was supplied through a third insulated rail between the tracks. A contact roller was used to collect the electricity. The world's first electric tram line opened in Lichterfelde near Berlin, Germany, in 1881. It was built by Werner von Siemens (see Gross-Lichterfelde Tramway and Berlin Straßenbahn). Volk's Electric Railway opened in 1883 in Brighton. Also in 1883, Mödling and Hinterbrühl Tram opened near Vienna in Austria. It was the first in the world in regular service powered from an overhead line. Five years later, in the U.S. electric trolleys were pioneered in 1888 on the Richmond Union Passenger Railway, using equipment designed by Frank J. Sprague.[6]

Much of the early development of electric locomotion was driven by the increasing use of tunnels, particularly in urban areas. Smoke from steam locomotives was noxious and municipalities were increasingly inclined to prohibit their use within their limits. The first electrically-worked underground line was the City and South London Railway, prompted by a clause in its enabling act prohibiting use of steam power.[7] It opened in 1890, using electric locomotives built by Mather and Platt. Electricity quickly became the power supply of choice for subways, abetted by the Sprague's invention of multiple-unit train control in 1897. Surface and elevated rapid transit systems generally used steam until forced to convert by ordinance.

The first use of electrification on a main line was on a four-mile stretch of the Baltimore Belt Line of the Baltimore and Ohio Railroad (B&O) in 1895 connecting the main portion of the B&O to the new line to New York through a series of tunnels around the edges of Baltimore's downtown. Parallel tracks on the Pennsylvania Railroad had shown that coal smoke from steam locomotives would be a major operating issue and a public nuisance. Three Bo+Bo units were initially used, at the south end of the electrified section; they coupled onto the locomotive and train and pulled it through the tunnels.[8] Railroad entrances to New York City required similar tunnels and the smoke problems were more acute there. A collision in the Park Avenue tunnel in 1902 led the New York State legislature to outlaw the use of smoke-generating locomotives south of the Harlem River after 1 July 1908. In response, electric locomotives began operation in 1904 on the New York Central Railroad. In the 1930s, the Pennsylvania Railroad, which had introduced electric locomotives because of the NYC regulation, electrified its entire territory east of Harrisburg, Pennsylvania.

The Chicago, Milwaukee, St. Paul and Pacific Railroad (the Milwaukee Road), the last transcontinental line to be built, electrified its lines across the Rocky Mountains and to the Pacific Ocean starting in 1915. A few East Coast lines, notably the Virginian Railway and the Norfolk and Western Railway, electrified short sections of their mountain crossings. However, by this point electrification in the United States was more associated with dense urban traffic and the use of electric locomotives declined in the face of dieselization.[9] Diesels shared some of the electric locomotive's advantages over steam and the cost of building and maintaining the power supply infrastructure, which discouraged new installations, brought on the elimination of most main-line electrification outside the Northeast. Except for a few captive systems (e.g. the Black Mesa and Lake Powell), by 2000 electrification was confined to the Northeast Corridor and some commuter service; even there, freight service was handled by diesels. Development continued in Europe, where electrification was widespread.

The first practical AC electric locomotive was designed by Charles Brown, then working for Oerlikon, Zürich. In 1891, Brown had demonstrated long-distance power transmission, using three-phase AC, between a hydro-electric plant at Lauffen am Neckar and Frankfurt am Main West, a distance of 280 km. Using experience he had gained while working for Jean Heilmann on steam-electric locomotive designs, Brown observed that three-phase motors had a higher power-to-weight ratio than DC motors and, because of the absence of a commutator, were simpler to manufacture and maintain.[10] However, they were much larger than the DC motors of the time and could not be mounted in underfloor bogies: they could only be carried within locomotive bodies.[11]

In 1894, Hungarian engineer Kálmán Kandó developed a new type 3-phase asynchronous electric drive motors and generators for electric locomotives. Kandó's early 1894 designs were first applied in a short three-phase AC tramway in Evian-les-Bains (France), which was constructed between 1896 and 1898.[12][13][14][15][16] In 1918,[17] Kandó invented and developed the rotary phase converter, enabling electric locomotives to use three-phase motors whilst supplied via a single overhead wire, carrying the simple industrial frequency (50 Hz) single phase AC of the high voltage national networks.[18]

In 1896, Oerlikon installed the first commercial example of the system on the Lugano Tramway. Each 30-tonne locomotive had two 110 kW (150 hp) motors run by three-phase 750 V 40 Hz fed from double overhead lines. Three-phase motors run at constant speed and provide regenerative braking, and are well suited to steeply graded routes, and the first main-line three-phase locomotives were supplied by Brown (by then in partnership with Walter Boveri) in 1899 on the 40 km Burgdorf—Thun line, Switzerland. The first implementation of industrial frequency single-phase AC supply for locomotives came from Oerlikon in 1901, using the designs of Hans Behn-Eschenburg and Emil Huber-Stockar; installation on the Seebach-Wettingen line of the Swiss Federal Railways was completed in 1904. The 15 kV, 50 Hz 345 kW (460 hp), 48 tonne locomotives used transformers and rotary converters to power DC traction motors.[19]

A prototype of a Ganz AC electric locomotive in Valtellina, Italy, 1901

Italian railways were the first in the world to introduce electric traction for the entire length of a main line rather than just a short stretch. The 106 km Valtellina line was opened on 4 September 1902, designed by Kandó and a team from the Ganz works.[20][18] The electrical system was three-phase at 3 kV 15 Hz. The voltage was significantly higher than used earlier and it required new designs for electric motors and switching devices.[21][22] The three-phase two-wire system was used on several railways in Northern Italy and became known as "the Italian system". Kandó was invited in 1905 to undertake the management of Società Italiana Westinghouse and led the development of several Italian electric locomotives.[21] During the period of electrification of the Italian railways, tests were made as to which type of power to use: in some sections there was a 3,600 V 162⁄3 Hz three-phase power supply, in others there was 1,500 V DC, 3 kV DC and 10 kV AC 45 Hz supply. After WW2, 3 kV DC power was chosen for the entire Italian railway system.[23] 1,500 V DC is still used on some lines near France and 25 kV 50 Hz is used by high-speed trains.[5]

A later development of Kandó, working with both the Ganz works and Societa Italiana Westinghouse, was an electro-mechanical converter, allowing the use of three-phase motors from single-phase AC, eliminating the need for two overhead wires.[24] In 1923, the first phase-converter locomotive in Hungary was constructed on the basis of Kandó's designs and serial production began soon after. The first installation, at 16 kV 50 Hz, was in 1932 on the 56 km section of the Hungarian State Railways between Budapest and Komárom. This proved successful and the electrification was extended to Hegyeshalom in 1934.[25]

A Swiss Re 420 leads a freight train down the South side of the Gotthard line, which was electrified in 1922. The masts and lines of the catenary can be seen.

In Europe, electrification projects initially focused on mountainous regions for several reasons: coal supplies were difficult, hydroelectric power was readily available, and electric locomotives gave more traction on steeper lines. This was particularly applicable in Switzerland, where close to 100% of lines are electrified. An important contribution to the wider adoption of AC traction came from SNCF of France after World War II. The company had assessed the industrial-frequency AC line routed through the steep Höllental Valley, Germany, which was under French administration following the war. After trials, the company decided that the performance of AC locomotives was sufficiently developed to allow all its future installations, regardless of terrain, to be of this standard, with its associated cheaper and more efficient infrastructure.[26] The SNCF decision, ignoring as it did the 2,000 miles (3,200 km) of high-voltage DC already installed on French routes, was influential in the standard selected for other countries in Europe.[26]

The 1960s saw the electrification of many European main lines. European electric locomotive technology had improved steadily from the 1920s onwards. By comparison, the Milwaukee Road class EP-2 (1918) weighed 240 t, with a power of 3,330 kW and a maximum speed of 112 km/h; in 1935, German E 18 had a power of 2,800 kW, but weighed only 108 tons and had a maximum speed of 150 km/h. On 29 March 1955, French locomotive CC 7107 reached 331 km/h. In 1960 the SJ Class Dm 3 locomotives on Swedish Railways produced a record 7,200 kW. Locomotives capable of commercial passenger service at 200 km/h appeared in Germany and France in the same period. Further improvements resulted from the introduction of electronic control systems, which permitted the use of increasingly lighter and more powerful motors that could be fitted inside the bogies (standardising from the 1990s onwards on asynchronous three-phase motors, fed through GTO-inverters).

In the 1980s, development of very high-speed service brought further electrification. The Japanese Shinkansen and the French TGV were the first systems for which devoted high-speed lines were built from scratch. Similar programs were undertaken in Italy, Germany and Spain; in the United States the only new main-line service was an extension of electrification over the Northeast Corridor from New Haven, Connecticut, to Boston, Massachusetts, though new electric light rail systems continued to be built.

On 2 September 2006, a standard production Siemens electric locomotive of the Eurosprinter type ES64-U4 (ÖBB Class 1216) achieved 357 km/h (221 mph), the record for a locomotive-hauled train, on the new line between Ingolstadt and Nuremberg.[27] This locomotive is now employed largely unmodified by ÖBB to haul their Railjet which is however limited to a top speed of 230 km/h due to economic and infrastructure concerns.

The most fundamental difference lies in the choice of AC or DC. The earliest systems used DC, as AC was not well understood and insulation material for high voltage lines was not available. DC locomotives typically run at relatively low voltage (600 to 3,000 volts); the equipment is therefore relatively massive because the currents involved are large in order to transmit sufficient power. Power must be supplied at frequent intervals as the high currents result in large transmission system losses.

As AC motors were developed, they became the predominant type, particularly on longer routes. High voltages (tens of thousands of volts) are used because this allows the use of low currents; transmission losses are proportional to the square of the current (e.g. twice the current means four times the loss). Thus, high power can be conducted over long distances on lighter and cheaper wires. Transformers in the locomotives transform this power to a low voltage and high current for the motors.[28] A similar high voltage, low current system could not be employed with direct current locomotives because there is no easy way to do the voltage/current transformation for DC so efficiently as achieved by AC transformers.

AC traction still occasionally uses dual overhead wires instead of single phase lines. The resulting three-phase current drives induction motors, which do not have sensitive commutators and permit easy realisation of a regenerative brake. Speed is controlled by changing the number of pole pairs in the stator circuit, with acceleration controlled by switching additional resistors in, or out, of the rotor circuit. The two-phase lines are heavy and complicated near switches, where the phases have to cross each other. The system was widely used in northern Italy until 1976 and is still in use on some Swiss rack railways. The simple feasibility of a fail-safe electric brake is an advantage of the system, while speed control and the two-phase lines are problematic.

Rectifier locomotives, which used AC power transmission and DC motors, were common, though DC commutators had problems both in starting and at low velocities.[further explanation needed] Today's advanced electric locomotives use brushless three-phase AC induction motors. These polyphase machines are powered from GTO-, IGCT- or IGBT-based inverters. The cost of electronic devices in a modern locomotive can be up to 50% of the cost of the vehicle.

Electric traction allows the use of regenerative braking, in which the motors are used as brakes and become generators that transform the motion of the train into electrical power that is then fed back into the lines. This system is particularly advantageous in mountainous operations, as descending locomotives can produce a large portion of the power required for ascending trains. Most systems have a characteristic voltage and, in the case of AC power, a system frequency. Many locomotives have been equipped to handle multiple voltages and frequencies as systems came to overlap or were upgraded. American FL9 locomotives were equipped to handle power from two different electrical systems and could also operate as diesel-electrics.

Third rail at the West Falls ChurchMetro station near Washington, D.C., electrified at 750 volts. The third rail is at the top of the image, with a white canopy above it. The two lower rails are the ordinary running rails; current from the third rail returns to the power station through these.

Electrical circuits require two connections (or for three phase AC, three connections). From the beginning, the track was used for one side of the circuit. Unlike model railroads the track normally supplies only one side, the other side(s) of the circuit being provided separately.

The original Baltimore and Ohio Railroad electrification used a sliding shoe in an overhead channel, a system quickly found to be unsatisfactory. It was replaced by a third rail, in which a pickup (the "shoe") rode underneath or on top of a smaller rail parallel to the main track, above ground level. There were multiple pickups on both sides of the locomotive in order to accommodate the breaks in the third rail required by trackwork. This system is preferred in subways because of the close clearances it affords.

Railways generally tend to prefer overhead lines, often called "catenaries" after the support system used to hold the wire parallel to the ground. Three collection methods are possible:

Trolley pole: a long flexible pole, which engages the line with a wheel or shoe.

Bow collector: a frame that holds a long collecting rod against the wire.

Pantograph: a hinged frame that holds the collecting shoes against the wire in a fixed geometry.

Of the three, the pantograph method is best suited for high-speed operation. Some locomotives use both overhead and third rail collection (e.g. British Rail Class 92). In Europe the recommended geometry and shape of pantographs are defined by standard EN 50367/IEC 60486[29]

During the initial development of railroad electrical propulsion, a number of drive systems were devised to couple the output of the traction motors to the wheels. Early locomotives used often jackshaft drives. In this arrangement, the traction motor is mounted within the body of the locomotive and drives the jackshaft through a set of gears. This system was employed because the first traction motors were too large and heavy to mount directly on the axles. Due to the number of mechanical parts involved, frequent maintenance was necessary. The jackshaft drive was abandoned for all but the smallest units when smaller and lighter motors were developed,

Several other systems were devised as the electric locomotive matured. The Buchli drive was a fully spring-loaded system, in which the weight of the driving motors was completely disconnected from the driving wheels. First used in electric locomotives from the 1920s, the Buchli drive was mainly used by the French SNCF and Swiss Federal Railways. The quill drive was also developed about this time and mounted the traction motor above or to the side of the axle and coupled to the axle through a reduction gear and a hollow shaft - the quill - flexibly connected to the driving axle. The Pennsylvania Railroad GG1 locomotive used a quill drive. Again, as traction motors continued to shrink in size and weight, quill drives gradually fell out of favour.

Another drive was the "bi-polar" system, in which the motor armature was the axle itself, the frame and field assembly of the motor being attached to the truck (bogie) in a fixed position. The motor had two field poles, which allowed a limited amount of vertical movement of the armature. This system was of limited value since the power output of each motor was limited. The EP-2 bi-polar electrics used by the Milwaukee Road compensated for this problem by using a large number of powered axles.

Modern electric locomotives, like their Diesel-electric counterparts, almost universally use axle-hung traction motors, with one motor for each powered axle. In this arrangement, one side of the motor housing is supported by plain bearings riding on a ground and polished journal that is integral to the axle. The other side of the housing has a tongue-shaped protuberance that engages a matching slot in the truck (bogie) bolster, its purpose being to act as a torque reaction device, as well as a support. Power transfer from motor to axle is effected by spur gearing, in which a pinion on the motor shaft engages a bull gear on the axle. Both gears are enclosed in a liquid-tight housing containing lubricating oil. The type of service in which the locomotive is used dictates the gear ratio employed. Numerically high ratios are commonly found on freight units, whereas numerically low ratios are typical of passenger engines.

The Whyte notation system for classifying steam locomotives is not adequate for describing the variety of electric locomotive arrangements, though the Pennsylvania Railroad applied classes to its electric locomotives as if they were steam. For example, the PRR GG1 class indicates that it is arranged like two 4-6-0 class G locomotives coupled back-to-back.

UIC classification system was typically used for electric locomotives, as it could handle the complex arrangements of powered and unpowered axles and could distinguish between coupled and uncoupled drive systems.

FS Class E656, an articulated Bo'-Bo'-Bo' locomotive, manages more easily the tight curves often found on the Italian railways

Electrification is widespread in Europe. Due to higher density schedules, operating costs are more dominant with respect to the infrastructure costs than in the U.S. and electric locomotives have much lower operating costs than diesels. In addition, governments were motivated to electrify their railway networks due to coal shortages experienced during the First and Second World Wars.

Diesel locomotives have less power compared to electric locomotives for the same weight and dimensions. For instance, the 2,200 kW of a modern British Rail Class 66 was matched in 1927 by the electric SBB-CFF-FFS Ae 4/7 (2,300 kW), which is lighter. However, for low speeds, tractive effort is more important than power. This is why diesel engines are competitive for slow freight traffic (as it is common in the U.S.) but not for passenger or mixed passenger/freight traffic like on many European railway lines, especially where heavy freight trains must be run at comparatively high speeds (80 km/h or more).

These factors led to high degrees of electrification in most European countries. In some countries like Switzerland, even electric shunters are common and many private sidings can be served by electric locomotives. During World War II, when materials to build new electric locomotives were not available, Swiss Federal Railways installed electric heating elements, fed from the overhead supply, in the boilers of some steam shunters to deal with the shortage of imported coal.[30][31]

Recent political developments in many European countries to enhance public transit have led to another boost for electric traction. High-speed trains like the TGV, ICE, AVE and Pendolino can only be run economically using electric traction and the operation of branch lines is usually less in deficit when using electric traction, due to cheaper and faster rolling stock and more passengers due to more frequent service and more comfort. In addition, gaps of un-electrified track are closed to avoid replacing electric locomotives by diesels for these sections. The necessary modernisation and electrification of these lines is possible due to financing of the railway infrastructure by the state.

Russia and other countries of the former USSR have a mix of 3,300 V DC and 25 kV AC for historical reasons.

The special "junction stations" (around 15 over the former USSR - Vladimir, Mariinsk near Krasnoyarsk etc.) have wiring switchable from DC to AC. Locomotive replacement is essential at these stations and is performed together with the contact wiring switching.

Most Soviet, Czech (the USSR ordered passenger electric locomotives from Skoda), Russian and Ukrainian locomotives can operate on AC or DC only. For instance, VL80 is an AC machine, with VL10 a DC version. There were some half-experimental small series like VL82, which could switch from AC to DC and were used in small amounts around the city of Kharkov in Ukraine. Also, the latest Russian passenger locomotive EP10 is dual-system.

Historically, 3,300 V DC was used for simplicity. The first experimental track was in Georgian mountains, then the suburban zones of the largest cities were electrified for EMUs - very advantageous due to much better dynamic of such a train compared to the steam one, which is important for suburban service with frequent stops. Then the large mountain line between Ufa and Chelyabinsk was electrified.

For some time, electric railways were only considered to be suitable for suburban or mountain lines. In around 1950, a decision was made (according to legend, by Joseph Stalin) to electrify the highly loaded plain prairie line of Omsk-Novosibirsk. After this, electrifying the major railroads at 3,000 V DC became mainstream.

25 kV AC started in the USSR in around 1960, when the industry managed to build the rectifier-based AC-wire DC-motor locomotive (all Soviet and Czech AC locomotives were such; only the post-Soviet ones switched to electronically controlled induction motors). The first major line with AC power was Mariinsk-Krasnoyarsk-Tayshet-Zima; the lines in European Russia like Moscow-Rostov-on-Don followed.

In 1990s, some DC lines were rebuilt as AC to allow the usage of the huge 10 MWt AC locomotive of VL85. The line around Irkutsk is one of them. The DC locomotives freed by this rebuild were transferred to the St Petersburg region.

The Trans-Siberian Railway has been partly electrified since 1929, entirely since 2002. The system is 25 kV AC 50 Hz after the junction station of Mariinsk near Krasnoyarsk, 3,000 V DC before it, and train weights are up to 6,000 tonnes.[32]

In North America, the flexibility of diesel locomotives and the relative low cost of their infrastructure has led them to prevail except where legal or operational constraints dictate the use of electricity. An example of the latter is the use of electric locomotives by Amtrak and commuter railroads in the Northeast. New Jersey Transit New York corridor uses ALP-46 electric locomotives, due to the prohibition on diesel operation in Penn Station and the Hudson and East River Tunnels leading to it. Some other trains to Penn Stations use dual-mode locomotives that can also operate off third-rail power in the tunnels and the station. Electric locomotives are planned for the California High Speed Rail system.

During the steam era, some mountainous areas were electrified but these have been discontinued. The junction between electrified and non-electrified territory is the locale of engine changes; for example, Amtrak trains had extended stops in New Haven, Connecticut, as locomotives were swapped, a delay which contributed to the decision to electrify the New Haven to Boston segment of the Northeast Corridor in 2000.[33]

Electrification systems used by the JR group, Japan's formerly state-owned operators, are 1,500 V DC and 20 kV AC for conventional lines and 25 kV AC for Shinkansen. Electrification at 600 V DC and 750 V DC are also seen in private lines. The frequency of the AC power supply is 50 Hz in Eastern Japan and 60 Hz in Western Japan.

Japan has come close to complete electrification largely due to the relatively short distances and mountainous terrain, which make electric service a particularly economical investment. Additionally, the mix of freight to passenger service is weighted much more toward passenger service (even in rural areas) than in many other countries, and this has helped drive government investment into electrification of many remote lines.

Electrification began in earnest for local railways in the 1920s and main lines electrification began following World War II using a universal 1,500 V DC standard and eventually, a 20 kV standard for rapid intercity main lines (often overlaying 1,500 V DC lines) and 25 kV AC for high-speed Shinkansen lines). Because most of the electrification infrastructure was destroyed in the war, the only variances to this standard with significant traffic are a few of the older subway lines in Tokyo and Osaka. The Tōkaidō Main Line, Japan's busiest line, completed electrification in 1956 and Tōkaidō Shinkansen was complete in 1964. By the mid 1970s, most main lines had been converted. During the 1970s and into the 1980s, when a fast-growing Japanese economy encouraged massive infrastructure spending, almost every line with any significant traffic was electrified. Though the massive debts incurred for these upgrades (along with the more publicised expense of Shinkansen expansions) led to the privatization and break-up of the national rail company. By the time of the breakup in 1987, electric service had penetrated to every line with significant traffic. In the 1990s, and 2000s, rural infrastructure was the focus of a lot of government stimulus funding and this included some rail electrification on infrequently used lines, and funding for expanding the Shinkansen network (which, as with all high speed trains, is electric). The latter was mostly in the form of loans rather than direct investment as in the former.

All mainline electrified routes in India use 25 kV AC railway electrification at 50 Hz. As of 2015[update], Indian railways haul 85% of freight and passenger traffic with electric locomotives. Urban rail transits in various cities, such as metro, monorail and tram, use 750 V DC electrification.

In both states, the use of electric locomotives on principal interurban routes proved to be a qualified success. In Victoria, because only one major line (the Gippsland line) had been electrified, the economic advantages of electric traction were not fully realised due to the need to change locomotives for trains that ran beyond the electrified network. VR's electric locomotive fleet was withdrawn from service by 1987[35] and the Gippsland line electrification was dismantled by 2004.[36] The 86 class locomotives introduced to NSW in 1983 had a relatively short life as the costs of changing locomotives at the extremities of the electrified network, together with the higher charges levied for electricity use, saw diesel-electric locomotives make inroads into the electrified network.[37] Electric power car trains are still used for urban passenger services.

Queensland Rail implemented electrification relatively recently and utilises the more recent 25 kV AC technology with around 1,000 km of the narrow gauge network now electrified. It operates a fleet of electric locomotives to transport coal for export, the most recent of which the 3,000 kW (4,020 HP) 3300/3400 Class.[38] Queensland Rail is currently rebuilding its 3100 and 3200 class locos into the 3700 class, which use AC traction and need only three locomotives on a coal train rather than five. Queensland Rail is getting 30 3800 class locomotives from Siemens in Munich, Germany, which will arrive during late 2008 to 2009. QRNational (Queensland Rail's coal and freight after separation) has increased the order of 3800 class locomotives. They continue to arrive late into 2010.

A battery-electric locomotive (or battery locomotive) is powered by on-board batteries; a kind of battery electric vehicle. Such locomotives are used where a conventional diesel or electric locomotive would be unsuitable.

Another use for battery locomotives is in industrial facilities where a combustion-powered locomotive (i.e., steam- or diesel-powered) could cause a safety issue due to the risks of fire, explosion or fumes in a confined space. Battery locomotives are preferred for mines where gas could be ignited by trolley-powered units arcing at the collection shoes, or where electrical resistance could develop in the supply or return circuits, especially at rail joints, and allow dangerous current leakage into the ground.[40]

An early example was at the Kennecott Copper Mine, Latouche, Alaska, where in 1917 the underground haulage ways were widened to enable working by two battery locomotives of 41⁄2 tons.[41] In 1928, Kennecott Copper ordered four 700-series electric locomotives with on-board batteries. These locomotives weighed 85 tons and operated on 750-volt overhead trolley wire with considerable further range whilst running on batteries.[42] The locomotives provided several decades of service using Nickel-iron battery (Edison) technology. The batteries were replaced with lead-acid batteries, and the locomotives were retired shortly afterward. All four locomotives were donated to museums, but one was scrapped. The others can be seen at the Boone and Scenic Valley Railroad, Iowa, and at the Western Railway Museum in Rio Vista, California.

1.
Virgin Trains
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Virgin Trains is a train operating company in the United Kingdom owned by Virgin Rail Group and Stagecoach that has operated the InterCity West Coast franchise since 9 March 1997. Virgin Trains operates long-distance passenger services on the West Coast Main Line between London, West Midlands, North West England, North Wales and Scotland. The service connects six of the UKs largest cities, London, Birmingham, Manchester, Liverpool, Glasgow and Edinburgh, Virgin Rail Group was awarded the InterCity West Coast franchise in January 1997 after beating Sea Containers and Stagecoach with operations commencing on 9 March 1997. In October 1998 Virgin Group sold 49% of the shares in Virgin Rail Group to Stagecoach, when Virgin won the franchise, Railtrack was to upgrade the West Coast Main Line to allow tilting trains to operate at 140 mph by 2005. Due to costs having blown out from £2.5 billion to £10 billion there were cutbacks to the upgrade, in May 1998 Virgin introduced new services from London Euston to Shrewsbury and Blackpool North. The former ceased in 1999, the latter in May 2003, in December 2014, a daily weekday service between London Euston and Blackpool North and a twice daily service between London Euston and Shrewsbury were reintroduced. In September 2004 a London Euston to Llandudno service was introduced ceasing in December 2008, in September 2005 Virgin introduced its first 125 mph timetable following the completion of Stage 1 of the upgrade. In December 2008 a Wrexham to London Euston service was introduced operating south in the morning with an evening return, in February 2009 an hourly London Euston to Chester service was introduced. From January 2009 Virgin Trains gradually rolled out a new Very High Frequency timetable to take advantage of the completed West Coast Main Line upgrade, there were many timetable changes from 8 December 2013. Edinburgh/Glasgow services now run to/from London and call at Sandwell & Dudley replacing the hourly Wolverhampton to Euston service, in addition most Liverpool services will additionally call at Crewe. This has resulted in the latter being serviced by four Virgin trains in each direction per hour to/from London instead of the previous two, Virgin Trains suffered poor punctuality compared with some other transport operators between 2001 and 2006, according to Office of Rail Regulation statistics. Punctuality did gradually improve until the introduction of a new timetable, following the upgrade of the West Coast Main Line, performance subsequently recovered and peaked during 2010-2011, but then fell again and reached a new low for the year ending 31 March 2013 of 83. 6%. Financial year to 31 March 2008,86. 2%, financial year to 31 March 2009,80. 0%. Financial year to 31 March 2010,84. 6%, financial year to 31 March 2011,86. 6%. Financial year to 31 March 2012,85. 9%, financial year to 31 March 2013,83. 6%. Financial year to 31 March 2014,85. 8%, financial year to 31 March 2015,84. 7%. Latest figures published by Network Rail for the period of 2013-2014 recorded PPM of 92. 2% for the period. The PPM performance for the period is down 2.7 percentage points on the figure from the same period last year

2.
British Rail Class 87
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The British Rail Class 87 is a type of electric locomotive built in 1973–75 by British Rail Engineering Limited. Thirty-six of these locomotives were built to passenger services over the West Coast Main Line. They were the flagships of British Rails electric locomotive fleet until the late 1980s, the privatisation of British Rail saw all but one of the fleet transferred to Virgin Trains. They continued their duties until the advent of the new Class 390 Pendolinos, there is only one Class 87 still in use in Britain,87002, owned by the AC Locomotive Group and solely used alongside 86101 for the occasional charter train. A large proportion of the fleet have now been exported to Bulgaria,87002 is currently hired by Serco to work the empty coaching stock of the Caledonian Sleeper services. A requirement for more locomotives came about after the electrification of the WCML was extended from Weaver Junction north of Crewe to Preston, Carlisle. Initially, three Class 86 locomotives were used as test-beds to trial equipment that would be used in the new locomotives, effectively, the power and speed of the Class 87 was increased over that of the Class 86. Power output was increased to 5000 hp to deal with the demanding gradients on the northern half of the WCML such as Shap Fell and Beattock Summit. The 87s were also fitted with multiple working equipment which enabled locomotives to work with members of the class while controlled by one driver. Whilst the first 35 locomotives were identical, the 36th was numbered 87101 and had major equipment differences from the rest of the class. While the 87/0s were fitted with a tap changer transformer and rectifiers,87101 had a new thyristor power control system. The locomotive, named Stephenson after transfer of the name from 87001, worked the same services as the locomotives for many years. This locomotive was in effect the prototype for the build of locomotives designated Class 90. The great majority of the Class 87s workload came on express services from London Euston to the North West. They did, however, see some use on freight, especially on heavy services that required two locomotives, in the late 1970s, British Rail named its entire Class 87 fleet, many receiving names previously carried by the Britannia steam locomotives. The rest were named after towns, cities or counties along the WCML, in the 1980s, British Rail locomotives were allocated to separate sectors and the 87/0s were transferred to InterCity, whilst 87101 went to work for Railfreight Distribution. As part of the privatisation of British Rail, all 35 passed to rolling stock leasing company Porterbrook and were leased to InterCity West Coast operator Virgin Trains in 1997. The locomotives continued to work the same services as before, the outward indication of the change of ownership being the repainting of the locomotives in the red Virgin Trains livery

3.
Carlisle, Cumbria
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Carlisle is a city and the county town of Cumbria. Historically in Cumberland, it is also the centre of the City of Carlisle district in North West England. Carlisle is located at the confluence of the rivers Eden, Caldew and it is the largest settlement in the county of Cumbria, and serves as the administrative centre for both Carlisle City Council and Cumbria County Council. At the time of the 2001 census, the population of Carlisle was 71,773, ten years later, at the 2011 census, the citys population had risen to 75,306, with 107,524 in the wider city. The early history of Carlisle is marked by its status as a Roman settlement, the castle now houses the Duke of Lancasters Regiment and the Border Regiment Museum. In the early 12th century, Henry I allowed the foundation of a priory in Carlisle, the town gained the status of a city when its diocese was formed in 1133, and the priory became Carlisle Cathedral. The introduction of textile manufacture during the Industrial Revolution began a process of transformation in Carlisle. This, combined with its position, allowed for the development of Carlisle as an important railway town. Nicknamed the Great Border City, Carlisle today is the cultural, commercial and industrial centre for north Cumbria. It is home to the campuses of the University of Cumbria. The former County Borough of Carlisle had held city status until the Local Government Act 1972 was enacted in 1974, what is known of the ancient history of Carlisle is derived mainly from archaeological evidence and the works of the Roman historian Tacitus. The earliest recorded inhabitants were the Carvetii tribe of Britons who made up the population of ancient Cumbria. According to Boethius and John of Fordun, Carlisle existed before the arrival of the Romans in Britain and was one of the strongest British towns at the time, in the time of the emperor Nero, it was said to have burned down. The Roman settlement was named Luguvalium, based on a name that has been reconstructed as Brittonic *Luguwaljon, of Luguwalos. This walled civitas, possibly the one in northwest Britain. In the year 79, the two Roman generals Cn, petillius Cerealis advanced through Solway as they continued their campaign further north. As a result, it is likely that control was achieved at Carlisle over anti-imperial groups. This is possibly indicated from the reconstruction of the fort at Carlisle in 83 using oak timbers from further afield, at this time the Roman fort was garrisoned by a 500-strong cavalry regiment, the Ala Gallorum Sebosiana

4.
Locomotive
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A locomotive or engine is a rail transport vehicle that provides the motive power for a train. A locomotive has no payload capacity of its own, and its purpose is to move the train along the tracks. In contrast, some trains have self-propelled payload-carrying vehicles and these are not normally considered locomotives, and may be referred to as multiple units, motor coaches or railcars. The use of these vehicles is increasingly common for passenger trains. Traditionally, locomotives pulled trains from the front, however, push-pull operation has become common, where the train may have a locomotive at the front, at the rear, or at each end. Prior to locomotives, the force for railroads had been generated by various lower-technology methods such as human power, horse power. The first successful locomotives were built by Cornish inventor Richard Trevithick, in 1804 his unnamed steam locomotive hauled a train along the tramway of the Penydarren ironworks, near Merthyr Tydfil in Wales. Although the locomotive hauled a train of 10 long tons of iron and 70 passengers in five wagons over nine miles, the locomotive only ran three trips before it was abandoned. Trevithick built a series of locomotives after the Penydarren experiment, including one which ran at a colliery in Tyneside in northern England, the first commercially successful steam locomotive was Matthew Murrays rack locomotive, Salamanca, built for the narrow gauge Middleton Railway in 1812. This was followed in 1813 by the Puffing Billy built by Christopher Blackett and William Hedley for the Wylam Colliery Railway, Puffing Billy is now on display in the Science Museum in London, the oldest locomotive in existence. In 1814 George Stephenson, inspired by the locomotives of Trevithick. He built the Blücher, one of the first successful flanged-wheel adhesion locomotives, Stephenson played a pivotal role in the development and widespread adoption of steam locomotives. His designs improved on the work of the pioneers, in 1825 he built the Locomotion for the Stockton and Darlington Railway, north east England, which became the first public steam railway. In 1829 he built The Rocket which was entered in and won the Rainhill Trials and this success led to Stephenson establishing his company as the pre-eminent builder of steam locomotives used on railways in the United Kingdom, the United States and much of Europe. The first inter city passenger railway, Liverpool and Manchester Railway, opened in 1830, there are a few basic reasons to isolate locomotive train power, as compared to self-propelled vehicles. Maximum utilization of power cars Separate locomotives facilitate movement of costly motive power assets as needed, flexibility Large locomotives can substitute for small locomotives when more power is required, for example, where grades are steeper. As needed, a locomotive can be used for freight duties. Obsolescence cycles Separating motive power from payload-hauling cars enables replacement without affecting the other, to illustrate, locomotives might become obsolete when their associated cars did not, and vice versa

5.
Electricity
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Electricity is the set of physical phenomena associated with the presence of electric charge. Although initially considered a separate to magnetism, since the development of Maxwells Equations both are recognized as part of a single phenomenon, electromagnetism. Various common phenomena are related to electricity, including lightning, static electricity, electric heating, electric discharges, in addition, electricity is at the heart of many modern technologies. The presence of a charge, which can be either positive or negative. On the other hand, the movement of charges, which is known as electric current. When a charge is placed in a location with non-zero electric field, the magnitude of this force is given by Coulombs Law. Thus, if that charge were to move, the field would be doing work on the electric charge. Electrical phenomena have been studied since antiquity, though progress in theoretical understanding remained slow until the seventeenth and eighteenth centuries. Even then, practical applications for electricity were few, and it would not be until the nineteenth century that engineers were able to put it to industrial and residential use. The rapid expansion in electrical technology at this time transformed industry, electricitys extraordinary versatility means it can be put to an almost limitless set of applications which include transport, heating, lighting, communications, and computation. Electrical power is now the backbone of modern industrial society, long before any knowledge of electricity existed, people were aware of shocks from electric fish. Ancient Egyptian texts dating from 2750 BCE referred to these fish as the Thunderer of the Nile, Electric fish were again reported millennia later by ancient Greek, Roman and Arabic naturalists and physicians. Patients suffering from such as gout or headache were directed to touch electric fish in the hope that the powerful jolt might cure them. Ancient cultures around the Mediterranean knew that certain objects, such as rods of amber, Thales was incorrect in believing the attraction was due to a magnetic effect, but later science would prove a link between magnetism and electricity. He coined the New Latin word electricus to refer to the property of attracting small objects after being rubbed and this association gave rise to the English words electric and electricity, which made their first appearance in print in Thomas Brownes Pseudodoxia Epidemica of 1646. Further work was conducted by Otto von Guericke, Robert Boyle, Stephen Gray, in the 18th century, Benjamin Franklin conducted extensive research in electricity, selling his possessions to fund his work. In June 1752 he is reputed to have attached a key to the bottom of a dampened kite string. A succession of jumping from the key to the back of his hand showed that lightning was indeed electrical in nature

6.
Overhead line
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An overhead line or overhead wire is used to transmit electrical energy to trams, trolleybuses, or trains. Overhead line is designed on the principle of one or more overhead wires situated over rail tracks, the feeder stations are usually fed from a high-voltage electrical grid. Electric trains that collect their current from overhead lines use a device such as a pantograph and it presses against the underside of the lowest overhead wire, the contact wire. Current collectors are electrically conductive and allow current to flow through to the train or tram, non-electric locomotives may pass along these tracks without affecting the overhead line, although there may be difficulties with overhead clearance. Alternative electrical power transmission schemes for trains include third rail, ground-level power supply, batteries and this article does not cover regenerative braking, where the traction motors act as generators to retard movement and return power to the overhead. To achieve good high-speed current collection, it is necessary to keep the wire geometry within defined limits. This is usually achieved by supporting the wire from a second wire known as the messenger wire or catenary. This wire approximates the path of a wire strung between two points, a catenary curve, thus the use of catenary to describe this wire or sometimes the whole system. This wire is attached to the wire at regular intervals by vertical wires known as droppers or drop wires. It is supported regularly at structures, by a pulley, link, the whole system is then subjected to a mechanical tension. As the contact wire makes contact with the pantograph, the insert on top of the pantograph is worn down. The straight wire between supports will cause the wire to cross over the whole surface of the pantograph as the train travels around the curve, causing uniform wear. On straight track, the wire is zigzagged slightly to the left. The movement of the wire across the head of the pantograph is called the sweep. The zigzagging of the line is not required for trolley poles. Depot areas tend to have only a wire and are known as simple equipment or trolley wire. When overhead line systems were first conceived, good current collection was only at low speeds. Compound equipment - uses a second wire, known as the auxiliary

7.
Third rail
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A third rail is a method of providing electric power to a railway locomotive or train, through a semi-continuous rigid conductor placed alongside or between the rails of a railway track. It is used typically in a transit or rapid transit system. Third rail systems are supplied from direct current electricity. The third-rail system of electrification is unrelated to the third used in dual gauge railways. Third-rail systems are a means of providing electric power to trains. On most systems, the rail is placed on the sleeper ends outside the running rails. The conductor rail is supported on ceramic insulators or insulated brackets, the trains have metal contact blocks called shoes which make contact with the conductor rail. The traction current is returned to the station through the running rails. The conductor rail is made of high conductivity steel. The conductor rails have to be interrupted at level crossings, crossovers, tapered rails are provided at the ends of each section, to allow a smooth engagement of the trains contact shoes. Because third rail systems present electric shock hazards close to the ground, a very high current must therefore be used to transfer adequate power, resulting in high resistive losses, and requiring relatively closely spaced feed points. The electrified rail threatens electrocution of anyone wandering or falling onto the tracks. This can be avoided by using platform screen doors, or the risk can be reduced by placing the rail on the side of the track away from the platform. There is also a risk of pedestrians walking onto the tracks at level crossings, the Paris Metro has graphic warning signs pointing out the danger of electrocution from urinating on third rails, precautions which Chicago did not have. The end ramps of conductor rails present a practical limitation on speed due to the impact of the shoe. The world speed record for a rail train is 174 km/h attained on 11 April 1988 by a British Class 442 EMU. In the event of a collision with an object, the beveled end ramps of bottom running systems can facilitate the hazard of having third rail penetrate the interior of a passenger car. This is believed to have contributed to the death of five passengers in the Valhalla train crash of 2015, third rail systems using top contact are prone to accumulations of snow, or ice formed from refrozen snow, and this can interrupt operations

8.
Battery (electricity)
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An electric battery is a device consisting of one or more electrochemical cells with external connections provided to power electrical devices such as flashlights, smartphones, and electric cars. When a battery is supplying power, its positive terminal is the cathode. The terminal marked negative is the source of electrons that when connected to a circuit will flow. It is the movement of ions within the battery which allows current to flow out of the battery to perform work. Historically the term specifically referred to a device composed of multiple cells. Primary batteries are used once and discarded, the materials are irreversibly changed during discharge. Common examples are the battery used for flashlights and a multitude of portable electronic devices. Secondary batteries can be discharged and recharged multiple times using mains power from a wall socket, examples include the lead-acid batteries used in vehicles and lithium-ion batteries used for portable electronics such as laptops and smartphones. According to a 2005 estimate, the battery industry generates US$48 billion in sales each year. Batteries have much lower energy than common fuels such as gasoline. This is somewhat offset by the efficiency of electric motors in producing mechanical work. The usage of battery to describe a group of electrical devices dates to Benjamin Franklin, alessandro Volta built and described the first electrochemical battery, the voltaic pile, in 1800. This was a stack of copper and zinc plates, separated by brine-soaked paper disks, Volta did not understand that the voltage was due to chemical reactions. Although early batteries were of value for experimental purposes, in practice their voltages fluctuated. It consisted of a pot filled with a copper sulfate solution, in which was immersed an unglazed earthenware container filled with sulfuric acid. These wet cells used liquid electrolytes, which were prone to leakage and spillage if not handled correctly, many used glass jars to hold their components, which made them fragile and potentially dangerous. These characteristics made wet cells unsuitable for portable appliances, near the end of the nineteenth century, the invention of dry cell batteries, which replaced the liquid electrolyte with a paste, made portable electrical devices practical. Batteries convert chemical energy directly to electrical energy, a battery consists of some number of voltaic cells

9.
Fuel cell
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A fuel cell is a device that converts the chemical energy from a fuel into electricity through a chemical reaction of positively charged hydrogen ions with oxygen or another oxidizing agent. Fuel cells can produce electricity continuously for as long as these inputs are supplied, the first fuel cells were invented in 1838. The first commercial use of fuel cells came more than a later in NASA space programs to generate power for satellites. Since then, fuel cells have been used in other applications. Fuel cells are used for primary and backup power for commercial, industrial and residential buildings and they are also used to power fuel cell vehicles, including forklifts, automobiles, buses, boats, motorcycles and submarines. There are many types of cells, but they all consist of an anode, a cathode. The anode and cathode contain catalysts that cause the fuel to undergo reactions that generate positively charged hydrogen ions and electrons. The hydrogen ions are drawn through the electrolyte after the reaction, at the same time, electrons are drawn from the anode to the cathode through an external circuit, producing direct current electricity. At the cathode, hydrogen ions, electrons, and oxygen react to form water, Individual fuel cells produce relatively small electrical potentials, about 0.7 volts, so cells are stacked, or placed in series, to create sufficient voltage to meet an applications requirements. In addition to electricity, fuel cells produce water, heat and, depending on the source, very small amounts of nitrogen dioxide. The energy efficiency of a cell is generally between 40–60%, or up to 85% efficient in cogeneration if waste heat is captured for use. The fuel cell market is growing, and in 2013 Pike Research estimated that the fuel cell market will reach 50 GW by 2020. The first references to hydrogen fuel cells appeared in 1838 and he used a combination of sheet iron, copper and porcelain plates, and a solution of sulphate of copper and dilute acid. In a letter to the publication written in December 1838 but published in June 1839. His letter discussed current generated from hydrogen and oxygen dissolved in water, grove later sketched his design, in 1842, in the same journal. The fuel cell he used similar materials to todays phosphoric-acid fuel cell. In 1939, British engineer Francis Thomas Bacon successfully developed a 5 kW stationary fuel cell and this became known as the Grubb-Niedrach fuel cell. GE went on to develop this technology with NASA and McDonnell Aircraft and this was the first commercial use of a fuel cell

10.
Prime mover (locomotive)
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In engineering, a prime mover is an engine that converts fuel to useful work. In locomotives, the mover is thus the source of power for its propulsion. Generally it is any locomotive powered by a combustion engine. In an engine-generator set, the engine is the prime mover, in a diesel-mechanical locomotive, the prime mover is the diesel engine that is mechanically coupled to the driving wheels. The prime mover can also be a gas turbine instead of a diesel engine, in either case, the generator, traction motors and interconnecting apparatus are considered to be the power transmission system and not part of the prime mover. A wired-electric or battery-electric locomotive has no prime mover, instead relying on an external power station. The engine and generator set of a locomotive are sometimes coupled as a removable unit called the power unit

11.
Diesel engine
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Diesel engines work by compressing only the air. This increases the air temperature inside the cylinder to such a degree that it ignites atomised diesel fuel that is injected into the combustion chamber. This contrasts with spark-ignition engines such as an engine or gas engine. In diesel engines, glow plugs may be used to aid starting in cold weather, or when the engine uses a lower compression-ratio, the original diesel engine operates on the constant pressure cycle of gradual combustion and produces no audible knock. Low-speed diesel engines can have an efficiency that exceeds 50%. Diesel engines may be designed as either two-stroke or four-stroke cycles and they were originally used as a more efficient replacement for stationary steam engines. Since the 1910s they have used in submarines and ships. Use in locomotives, trucks, heavy equipment and electricity generation plants followed later, in the 1930s, they slowly began to be used in a few automobiles. Since the 1970s, the use of engines in larger on-road and off-road vehicles in the US increased. According to the British Society of Motor Manufacturing and Traders, the EU average for diesel cars accounts for 50% of the total sold, including 70% in France and 38% in the UK. The worlds largest diesel engine is currently a Wärtsilä-Sulzer RTA96-C Common Rail marine diesel, the definition of a Diesel engine to many has become an engine that uses compression ignition. To some it may be an engine that uses heavy fuel oil, to others an engine that does not use spark ignition. However the original cycle proposed by Rudolf Diesel in 1892 was a constant temperature cycle which would require higher compression than what is needed for compression ignition. Diesels idea was to compress the air so tightly that the temperature of the air would exceed that of combustion, to make this more clear, let it be assumed that the subsequent combustion shall take place at a temperature of 700°. Then in that case the pressure must be sixty-four atmospheres, or for 800° centigrade the pressure must be ninety atmospheres. In later years Diesel realized his original cycle would not work, Diesel describes the cycle in his 1895 patent application. Notice that there is no longer a mention of compression temperatures exceeding the temperature of combustion, now all that is mentioned is the compression must be high enough for ignition. In 1806 Claude and Nicéphore Niépce developed the first known internal combustion engine, the Pyréolophore fuel system used a blast of air provided by a bellows to atomize Lycopodium

12.
Gas turbine
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A gas turbine, also called a combustion turbine, is a type of internal combustion engine. It has an upstream rotating compressor coupled to a turbine. The basic operation of the gas turbine is similar to that of the power plant except that the working fluid is air instead of water. Fresh atmospheric air flows through a compressor that brings it to higher pressure, energy is then added by spraying fuel into the air and igniting it so the combustion generates a high-temperature flow. This high-temperature high-pressure gas enters a turbine, where it expands down to the exhaust pressure, the turbine shaft work is used to drive the compressor and other devices such as an electric generator that may be coupled to the shaft. The energy that is not used for shaft work comes out in the exhaust gases, the purpose of the gas turbine determines the design so that the most desirable energy form is maximized. Gas turbines are used to power aircraft, trains, ships, electrical generators,50, Heros Engine — Apparently, Heros steam engine was taken to be no more than a toy, and thus its full potential not realized for centuries. 1000, The Trotting Horse Lamp was used by the Chinese at lantern fairs as early as the Northern Song dynasty. When the lamp is lit, the heated airflow rises and drives an impeller with horse-riding figures attached on it,1629, Jets of steam rotated an impulse turbine that then drove a working stamping mill by means of a bevel gear, developed by Giovanni Branca. 1678, Ferdinand Verbiest built a model carriage relying on a jet for power. 1791, A patent was given to John Barber, an Englishman and his invention had most of the elements present in the modern day gas turbines. The turbine was designed to power a horseless carriage,1861, British patent no.1633 was granted to Marc Antoine Francois Mennons for a Caloric engine. The patent shows that it was a gas turbine and the show it applied to a locomotive. Also named in the patent was Nicolas de Telescheff, a Russian aviation pioneer,1872, A gas turbine engine was designed by Franz Stolze, but the engine never ran under its own power. 1894, Sir Charles Parsons patented the idea of propelling a ship with a turbine, and built a demonstration vessel. This principle of propulsion is still of some use,1895, Three 4-ton 100 kW Parsons radial flow generators were installed in Cambridge Power Station, and used to power the first electric street lighting scheme in the city. 1899, Charles Gordon Curtis patented the first gas engine in the USA. 1900, Sanford Alexander Moss submitted a thesis on gas turbines, in 1903, Moss became an engineer for General Electrics Steam Turbine Department in Lynn, Massachusetts

13.
Diesel-electric transmission
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Diesel-electric transmission, or diesel-electric powertrain is used by a number of vehicle and ship types for providing locomotion. A diesel-electric transmission system includes a diesel engine connected to an electrical generator, before diesel engines came into widespread use, a similar system, using a petrol engine and called petrol-electric or gas-electric, was sometimes used. Diesel-electric transmission is used on railways by diesel locomotives and diesel electric multiple units. Diesel-electric systems are used in submarines and surface ships and some land vehicles. In some high-efficiency applications, electrical energy may be stored in rechargeable batteries, the first diesel motorship was also the first diesel-electric ship, the Russian tanker Vandal from Branobel, which was launched in 1903. Steam turbine-electric propulsion has been in use since the 1920s, using diesel-electric powerplants in surface ships has increased lately, the Finnish coastal defence ships Ilmarinen and Väinämöinen laid down in 1928–1929, were among the first surface ships to use diesel-electric transmission. Later, the technology was used in diesel powered icebreakers, in World War II the United States built diesel-electric surface warships. Due to machinery shortages destroyer escorts of the Evarts and Cannon classes were diesel-electric, the Wind-class icebreakers, on the other hand, were designed for diesel-electric propulsion because of its flexibility and resistance to damage. An example of this is Harmony of the Seas, the largest passenger ship as of 2016 and this provides a relatively simple way to use the high-speed, low-torque output of a turbine to drive a low-speed propeller, without the need for excessive reduction gearing. Early submarines used a mechanical connection between the engine and propeller, switching between diesel engines for surface running, and electric motors for submerged propulsion. This was effectively a type of hybrid, since the motor. On the surface, the motor was used as a generator to recharge the batteries, the engine would be disconnected for submerged operation, with batteries powering the electric motor and supplying all other power as well. The concept was pioneered in 1929 in the S-class submarines S-3, S-6, the first production submarines with this system were the Porpoise-class, and it was used on most subsequent US diesel submarines through the 1960s. This mechanically isolates the engine compartment from the outer pressure hull. Some nuclear submarines also use a similar propulsion system, with propulsion turbo generators driven by reactor plant steam. During World War I, there was a strategic need for rail engines without plumes of smoke above them, diesel technology was not yet sufficiently developed but a few precursor attempts were made, especially for petrol-electric transmissions by the French and British. About 300 of these locomotives, only 96 being standard gauge, were in use at various points in the conflict, even before the war, the GE 57-ton gas-electric boxcab had been produced in the USA. In the 1920s, diesel-electric technology first saw limited use in switchers, locomotives used for moving trains around in railroad yards, an early company offering Oil-Electric locomotives was the American Locomotive Company

14.
Gas turbine-electric locomotive
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A gas turbine - electric locomotive, or GTEL, is a locomotive that uses a gas turbine to drive an electric generator or alternator. The electric current thus produced is used to power traction motors and this type of locomotive was first experimented with during the Second World War, but reached its peak in the 1950s to 1960s. Few locomotives use this system today, a GTEL uses a turbo-electric drivetrain in which a turboshaft engine drives an electrical generator or alternator via a system of gears. The electrical power is distributed to power the motors that drive the locomotive. In overall terms the system is similar to a conventional diesel-electric. A gas turbine offers some advantages over a piston engine, there are few moving parts, decreasing the need for lubrication and potentially reducing maintenance costs, and the power-to-weight ratio is much higher. A turbine of a power output is also physically smaller than an equally powerful piston engine. However, a power output and efficiency both drop dramatically with rotational speed, unlike a piston engine, which has a comparatively flat power curve. This makes GTEL systems useful primarily for long-distance high-speed runs, Union Pacific operated the largest fleet of such locomotives of any railroad in the world, and was the only railroad to use them for hauling freight. Most other GTELs have been built for passenger trains. With a rise in costs, gas turbine locomotives became uneconomical to operate. Additionally, Union Pacifics locomotives required more maintenance than originally anticipated, in 1939 the Swiss Federal Railways ordered a GTEL with a 1,620 kW of maximum engine power from Brown Boveri. It was completed in 1941, and then underwent testing before entering regular service, the Am 4/6 was the first gas turbine - electric locomotive. It was intended primarily to work light, fast, passenger trains on routes which normally handle insufficient traffic to justify electrification, two gas turbine locomotives of different design,18000 and 18100 were ordered by the Great Western Railway, but completed for the newly nationalised British Railways. 18000 was built by Brown Boveri and delivered in 1949 and it was a 1840 kW GTEL, ordered by the GWR and used for express passenger services. 18100 was built by Metropolitan-Vickers and delivered in 1951 and it had an aircraft-type gas turbine of 2.2 MW. Maximum speed was 90 miles per hour, the British Rail APT-E, prototype of the Advanced Passenger Train, was turbine-powered. Like the French TGV, later models were electric instead and this choice was made because British Leyland, the turbine supplier, ceased production of the model used in the APT-E

15.
Transmission (mechanics)
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A transmission is a machine in a power transmission system, which provides controlled application of the power. Often the term refers simply to the gearbox that uses gears and gear trains to provide speed. In British English, the term refers to the whole drivetrain, including clutch, gearbox, prop shaft, differential. In American English, however, the term more specifically to the gearbox alone. The most common use is in vehicles, where the transmission adapts the output of the internal combustion engine to the drive wheels. Such engines need to operate at a high rotational speed, which is inappropriate for starting, stopping. The transmission reduces the engine speed to the slower wheel speed. Transmissions are also used on bicycles, fixed machines. Often, a transmission has multiple gear ratios with the ability to switch between them as speed varies and this switching may be done manually or automatically. Directional control may also be provided, single-ratio transmissions also exist, which simply change the speed and torque of motor output. The output of the transmission is transmitted via the driveshaft to one or more differentials, while a differential may also provide gear reduction, its primary purpose is to permit the wheels at either end of an axle to rotate at different speeds as it changes the direction of rotation. Conventional gear/belt transmissions are not the mechanism for speed/torque adaptation. Alternative mechanisms include torque converters and power transformation, automatic transmissions use a valve body to shift gears using fluid pressures in conjunction with an ecm. Early transmissions included the right-angle drives and other gearing in windmills, horse-powered devices, and steam engines, in support of pumping, milling, most modern gearboxes are used to increase torque while reducing the speed of a prime mover output shaft. This means that the shaft of a gearbox rotates at a slower rate than the input shaft. A gearbox can be set up to do the opposite and provide an increase in speed with a reduction of torque. Some of the simplest gearboxes merely change the rotational direction of power transmission. Many typical automobile transmissions include the ability to select one of several gear ratios, in this case, most of the gear ratios are used to slow down the output speed of the engine and increase torque

16.
Electric motor
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An electric motor is an electrical machine that converts electrical energy into mechanical energy. The reverse of this is the conversion of energy into electrical energy and is done by an electric generator. In normal motoring mode, most electric motors operate through the interaction between an electric motors magnetic field and winding currents to generate force within the motor, small motors may be found in electric watches. General-purpose motors with highly standardized dimensions and characteristics provide convenient mechanical power for industrial use, the largest of electric motors are used for ship propulsion, pipeline compression and pumped-storage applications with ratings reaching 100 megawatts. Electric motors may be classified by electric power source type, internal construction, application, type of motion output, perhaps the first electric motors were simple electrostatic devices created by the Scottish monk Andrew Gordon in the 1740s. The theoretical principle behind production of force by the interactions of an electric current. The conversion of energy into mechanical energy by electromagnetic means was demonstrated by the British scientist Michael Faraday in 1821. A free-hanging wire was dipped into a pool of mercury, on which a permanent magnet was placed, when a current was passed through the wire, the wire rotated around the magnet, showing that the current gave rise to a close circular magnetic field around the wire. This motor is often demonstrated in experiments, brine substituting for toxic mercury. Though Barlows wheel was a refinement to this Faraday demonstration. In 1827, Hungarian physicist Ányos Jedlik started experimenting with electromagnetic coils, after Jedlik solved the technical problems of the continuous rotation with the invention of the commutator, he called his early devices electromagnetic self-rotors. Although they were used only for instructional purposes, in 1828 Jedlik demonstrated the first device to contain the three components of practical DC motors, the stator, rotor and commutator. The device employed no permanent magnets, as the fields of both the stationary and revolving components were produced solely by the currents flowing through their windings. His motor set a record which was improved only four years later in September 1838 by Jacobi himself. His second motor was powerful enough to drive a boat with 14 people across a wide river and it was not until 1839/40 that other developers worldwide managed to build motors of similar and later also of higher performance. The first commutator DC electric motor capable of turning machinery was invented by the British scientist William Sturgeon in 1832, following Sturgeons work, a commutator-type direct-current electric motor made with the intention of commercial use was built by the American inventor Thomas Davenport, which he patented in 1837. The motors ran at up to 600 revolutions per minute, and powered machine tools, due to the high cost of primary battery power, the motors were commercially unsuccessful and Davenport went bankrupt. Several inventors followed Sturgeon in the development of DC motors but all encountered the same battery power cost issues, no electricity distribution had been developed at the time

17.
Renewable energy
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Renewable energy is energy that is collected from renewable resources, which are naturally replenished on a human timescale, such as sunlight, wind, rain, tides, waves, and geothermal heat. Renewable energy often provides energy in four important areas, electricity generation, air and water heating/cooling, transportation, based on REN21s 2016 report, renewables contributed 19. 2% to humans global energy consumption and 23. 7% to their generation of electricity in 2014 and 2015, respectively. This energy consumption is divided as 8. 9% coming from biomass,4. 2% as heat energy,3. 9% hydro electricity and 2. 2% is electricity from wind, solar, geothermal. Worldwide investments in renewable technologies amounted to more than US$286 billion in 2015, with countries like China, globally, there are an estimated 7.7 million jobs associated with the renewable energy industries, with solar photovoltaics being the largest renewable employer. As of 2015 worldwide, more than half of all new electricity capacity installed was renewable, Renewable energy resources exist over wide geographical areas, in contrast to other energy sources, which are concentrated in a limited number of countries. Rapid deployment of energy and energy efficiency is resulting in significant energy security, climate change mitigation. In international public opinion there is strong support for promoting renewable sources such as solar power. At the national level, at least 30 nations around the already have renewable energy contributing more than 20 percent of energy supply. National renewable energy markets are projected to continue to grow strongly in the coming decade, for example, in Denmark the government decided to switch the total energy supply to 100% renewable energy by 2050. While many renewable energy projects are large-scale, renewable technologies are also suited to rural and remote areas and developing countries, United Nations Secretary-General Ban Ki-moon has said that renewable energy has the ability to lift the poorest nations to new levels of prosperity. Renewable energy systems are becoming more efficient and cheaper. Their share of energy consumption is increasing. Growth in consumption of coal and oil could end by 2020 due to increased uptake of renewables, in its various forms, it derives directly from the sun, or from heat generated deep within the earth. Included in the definition is electricity and heat generated from solar, wind, ocean, hydropower, biomass, geothermal resources, rapid deployment of renewable energy and energy efficiency, and technological diversification of energy sources, would result in significant energy security and economic benefits. New government spending, regulation and policies helped the industry weather the financial crisis better than many other sectors. As of 2011, small solar PV systems provide electricity to a few million households, United Nations Secretary-General Ban Ki-moon has said that renewable energy has the ability to lift the poorest nations to new levels of prosperity. At the national level, at least 30 nations around the already have renewable energy contributing more than 20% of energy supply. Some countries have much higher long-term policy targets of up to 100% renewables, outside Europe, a diverse group of 20 or more other countries target renewable energy shares in the 2020–2030 time frame that range from 10% to 50%

18.
Geothermal power
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Geothermal power is power generated by geothermal energy. Technologies in use include dry steam power stations, flash steam power stations, Geothermal electricity generation is currently used in 24 countries, while geothermal heating is in use in 70 countries. As of 2015, worldwide geothermal power capacity amounts to 12.8 gigawatts, International markets grew at an average annual rate of 5 percent over the last three years and global geothermal power capacity is expected to reach 14. 5–17.6 GW by 2020. Countries generating more than 15 percent of their electricity from geothermal sources include El Salvador, Kenya, Geothermal power is considered to be a sustainable, renewable source of energy because the heat extraction is small compared with the Earths heat content. In the 20th century, demand for electricity led to the consideration of geothermal power as a generating source, prince Piero Ginori Conti tested the first geothermal power generator on 4 July 1904 in Larderello, Italy. It successfully lit four light bulbs, later, in 1911, the worlds first commercial geothermal power station was built there. Experimental generators were built in Beppu, Japan and the Geysers, California, in the 1920s, in 1958, New Zealand became the second major industrial producer of geothermal electricity when its Wairakei station was commissioned. Wairakei was the first station to use flash steam technology, in 1960, Pacific Gas and Electric began operation of the first successful geothermal electric power station in the United States at The Geysers in California. The original turbine lasted for more than 30 years and produced 11 MW net power, the binary cycle power station was first demonstrated in 1967 in Russia and later introduced to the USA in 1981, following the 1970s energy crisis and significant changes in regulatory policies. This technology allows the use of lower temperature resources than were previously recoverable. In 2006, a binary cycle station in Chena Hot Springs, Alaska, came on-line, Geothermal electric stations have until recently been built exclusively where high temperature geothermal resources are available near the surface. The development of binary cycle power plants and improvements in drilling, demonstration projects are operational in Landau-Pfalz, Germany, and Soultz-sous-Forêts, France, while an earlier effort in Basel, Switzerland was shut down after it triggered earthquakes. Other demonstration projects are under construction in Australia, the United Kingdom, the thermal efficiency of geothermal electric stations is low, around 7–10%, because geothermal fluids are at a low temperature compared with steam from boilers. By the laws of thermodynamics this low temperature limits the efficiency of engines in extracting useful energy during the generation of electricity. Exhaust heat is wasted, unless it can be used directly and locally, for example in greenhouses, timber mills, and district heating. The efficiency of the system does not affect operational costs as it would for a coal or other fossil fuel plant, in order to produce more energy than the pumps consume, electricity generation requires high temperature geothermal fields and specialized heat cycles. Because geothermal power does not rely on sources of energy, unlike, for example, wind or solar. However the global average capacity factor was 74. 5% in 2008, the earth’s heat content is about 1031 joules

19.
Hydroelectricity
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Hydroelectricity is electricity produced from hydropower. In 2015 hydropower generated 16. 6% of the total electricity and 70% of all renewable electricity. Hydropower is produced in 150 countries, with the Asia-Pacific region generating 33 percent of global hydropower in 2013, China is the largest hydroelectricity producer, with 920 TWh of production in 2013, representing 16.9 percent of domestic electricity use. The cost of hydroelectricity is relatively low, making it a source of renewable electricity. The hydro station consumes no water, unlike coal or gas plants, the average cost of electricity from a hydro station larger than 10 megawatts is 3 to 5 U. S. cents per kilowatt-hour. With a dam and reservoir it is also a source of electricity since the amount produced by the station can be changed up or down very quickly to adapt to changing energy demands. Once a hydroelectric complex is constructed, the project produces no direct waste, Hydropower has been used since ancient times to grind flour and perform other tasks. In the mid-1770s, French engineer Bernard Forest de Bélidor published Architecture Hydraulique which described vertical-, by the late 19th century, the electrical generator was developed and could now be coupled with hydraulics. The growing demand for the Industrial Revolution would drive development as well, in 1878 the worlds first hydroelectric power scheme was developed at Cragside in Northumberland, England by William George Armstrong. It was used to power an arc lamp in his art gallery. The old Schoelkopf Power Station No.1 near Niagara Falls in the U. S. side began to produce electricity in 1881. The first Edison hydroelectric power station, the Vulcan Street Plant, began operating September 30,1882, in Appleton, Wisconsin, by 1886 there were 45 hydroelectric power stations in the U. S. and Canada. By 1889 there were 200 in the U. S. alone, at the beginning of the 20th century, many small hydroelectric power stations were being constructed by commercial companies in mountains near metropolitan areas. Grenoble, France held the International Exhibition of Hydropower and Tourism with over one million visitors, by 1920 as 40% of the power produced in the United States was hydroelectric, the Federal Power Act was enacted into law. The Act created the Federal Power Commission to regulate hydroelectric power stations on federal land, as the power stations became larger, their associated dams developed additional purposes to include flood control, irrigation and navigation. Federal funding became necessary for development and federally owned corporations, such as the Tennessee Valley Authority. Hydroelectric power stations continued to become larger throughout the 20th century, Hydropower was referred to as white coal for its power and plenty. Hoover Dams initial 1,345 MW power station was the worlds largest hydroelectric station in 1936

20.
Nuclear power
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Nuclear power is the use of nuclear reactions that release nuclear energy to generate heat, which most frequently is then used in steam turbines to produce electricity in a nuclear power plant. The term includes nuclear fission, nuclear decay and nuclear fusion, since all electricity supplying technologies use cement, etc. during construction, emissions are yet to be brought to zero. Each result is contrasted with coal and fossil gas at 820 and 490 g CO2 eq/kWh, there is a social debate about nuclear power. Proponents, such as the World Nuclear Association and Environmentalists for Nuclear Energy, contend that nuclear power is a safe, opponents, such as Greenpeace International and NIRS, contend that nuclear power poses many threats to people and the environment. These include the Chernobyl disaster which occurred in 1986, the Fukushima Daiichi nuclear disaster, there have also been some nuclear submarine accidents. Energy production from coal, petroleum, natural gas and hydroelectricity has caused a number of fatalities per unit of energy generated due to air pollution. In 2015, Ten new reactors were connected to the grid, seven reactors were permanently shut down. 441 reactors had a net capacity of 382,855 megawatts of electricity. 67 new nuclear reactors were under construction, Most of the new activity is in China where there is an urgent need to control pollution from coal plants. In October 2016, Watts Bar 2 became the first new United States reactor to enter commercial operation since 1996. The same year, his doctoral student James Chadwick discovered the neutron, further work by Enrico Fermi in the 1930s focused on using slow neutrons to increase the effectiveness of induced radioactivity. Experiments bombarding uranium with neutrons led Fermi to believe he had created a new, transuranic element and they determined that the relatively tiny neutron split the nucleus of the massive uranium atoms into two roughly equal pieces, contradicting Fermi. Numerous scientists, including Leó Szilárd, who was one of the first, recognized that if fission reactions released additional neutrons, a self-sustaining nuclear chain reaction could result. In the United States, where Fermi and Szilárd had both emigrated, this led to the creation of the first man-made reactor, known as Chicago Pile-1, which achieved criticality on December 2,1942. In 1945, the pocketbook The Atomic Age heralded the untapped atomic power in everyday objects and depicted a future where fossil fuels would go unused. One science writer, David Dietz, wrote that instead of filling the gas tank of a car two or three times a week, people travel for a year on a pellet of atomic energy the size of a vitamin pill. The United Kingdom, Canada, and the USSR proceeded over the course of the late 1940s, electricity was generated for the first time by a nuclear reactor on December 20,1951, at the EBR-I experimental station near Arco, Idaho, which initially produced about 100 kW. Work was also researched in the US on nuclear marine propulsion

21.
Solar power
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Solar power is the conversion of energy from sunlight into electricity, either directly using photovoltaics, or indirectly using concentrated solar power. Concentrated solar power systems use lenses or mirrors and tracking systems to focus a large area of sunlight into a small beam, Photovoltaic cells convert light into an electric current using the photovoltaic effect. Most solar installations would be in China and India, Solar PV is rapidly becoming an inexpensive, low-carbon technology to harness renewable energy from the Sun. The current largest photovoltaic power station in the world is the 850 MW Longyangxia Dam Solar Park, in Qinghai, commercial concentrated solar power plants were first developed in the 1980s. The 392 MW Ivanpah installation is the largest concentrating solar power plant in the world, long distance transmission allows remote renewable energy resources to displace fossil fuel consumption. Solar power plants use one of two technologies, Photovoltaic systems use solar panels, either on rooftops or in ground-mounted solar farms, concentrated solar power plants use solar thermal energy to make steam, that is thereafter converted into electricity by a turbine. A solar cell, or photovoltaic cell, is a device that converts light into electric current using the photovoltaic effect, the first solar cell was constructed by Charles Fritts in the 1880s. The German industrialist Ernst Werner von Siemens was among those who recognized the importance of this discovery, following the work of Russell Ohl in the 1940s, researchers Gerald Pearson, Calvin Fuller and Daryl Chapin created the silicon solar cell in 1954. These early solar cells cost 286 USD/watt and reached efficiencies of 4. 5–6%, the array of a photovoltaic power system, or PV system, produces direct current power which fluctuates with the sunlights intensity. For practical use this usually requires conversion to certain desired voltages or alternating current, multiple solar cells are connected inside modules. Modules are wired together to form arrays, then tied to an inverter, which produces power at the voltage, and for AC. Many residential PV systems are connected to the grid wherever available, in these grid-connected PV systems, use of energy storage is optional. In certain applications such as satellites, lighthouses, or in developing countries, batteries or additional power generators are often added as back-ups, such stand-alone power systems permit operations at night and at other times of limited sunlight. Concentrated solar power, also called concentrated solar thermal, uses lenses or mirrors, contrary to photovoltaics – which converts light directly into electricity – CSP uses the heat of the suns radiation to generate electricity from conventional steam-driven turbines. A wide range of concentrating technologies exists, among the best known are the trough, the compact linear Fresnel reflector, the Stirling dish. Various techniques are used to track the sun and focus light, in all of these systems a working fluid is heated by the concentrated sunlight, and is then used for power generation or energy storage. Thermal storage efficiently allows up to 24-hour electricity generation, a parabolic trough consists of a linear parabolic reflector that concentrates light onto a receiver positioned along the reflectors focal line. The receiver is a tube positioned right above the middle of the mirror and is filled with a working fluid

22.
Wind turbine
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A wind turbine is a device that converts the winds kinetic energy into electrical power. Wind turbines are manufactured in a range of vertical and horizontal axis types. The smallest turbines are used for such as battery charging for auxiliary power for boats or caravans or to power traffic warning signs. Slightly larger turbines can be used for making contributions to a power supply while selling unused power back to the utility supplier via the electrical grid. Wind turbines were used in Persia about 500–900 A. D, the windwheel of Hero of Alexandria marks one of the first known instances of wind powering a machine in history. However, the first known practical wind turbines were built in Sistan and these Panemone were vertical axle wind turbines, which had long vertical drive shafts with rectangular blades. Made of six to twelve sails covered in reed matting or cloth material, these turbines were used to grind grain or draw up water. Wind turbines first appeared in Europe during the Middle Ages, the first historical records of their use in England date to the 11th or 12th centuries and there are reports of German crusaders taking their windmill-making skills to Syria around 1190. By the 14th century, Dutch wind turbines were in use to areas of the Rhine delta. Advanced wind mills were described by Croatian inventor Fausto Veranzio, in his book Machinae Novae he described vertical axis wind turbines with curved or V-shaped blades. The first electricity-generating wind turbine was a battery charging machine installed in July 1887 by Scottish academic James Blyth to light his home in Marykirk. Some months later American inventor Charles F, although Blyths turbine was considered uneconomical in the United Kingdom electricity generation by wind turbines was more cost effective in countries with widely scattered populations. In Denmark by 1900, there were about 2500 windmills for mechanical loads such as pumps and mills, the largest machines were on 24-meter towers with four-bladed 23-meter diameter rotors. By 1908 there were 72 wind-driven electric generators operating in the United States from 5 kW to 25 kW, around the time of World War I, American windmill makers were producing 100,000 farm windmills each year, mostly for water-pumping. By the 1930s, wind generators for electricity were common on farms, in this period, high-tensile steel was cheap, and the generators were placed atop prefabricated open steel lattice towers. A forerunner of modern wind generators was in service at Yalta. This was a 100 kW generator on a 30-meter tower, connected to the local 6.3 kV distribution system and it was reported to have an annual capacity factor of 32 percent, not much different from current wind machines. In the autumn of 1941, the first megawatt-class wind turbine was synchronized to a utility grid in Vermont, the Smith-Putnam wind turbine only ran for 1,100 hours before suffering a critical failure

23.
Commuter rail
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Trains operate following a schedule, at speeds varying from 50 to 200 km/h. Distance charges or zone pricing may be used and they primarily serve lower density suburban areas, and often share right-of-way with intercity or freight trains. Some services operate only during peak hours and others uses fewer departures during off peak hours, average speeds are high, often 50 km/h or higher. These higher speeds better serve the longer distances involved, some services include express services which skip some stations in order to run faster and separate longer distance riders from short-distance ones. The general range of commuter trains distance varies between 15 and 200 km, sometimes long distances can be explained by that the train runs between two or several cities. Distances between stations may vary, but are much longer than those of urban rail systems. In city centers the train either has a station or passes through the city centre with notably fewer station stops than those of urban rail systems. Toilets are often available on trains and in stations. Their ability to coexist with freight or intercity services in the same right-of-way can drastically reduce system construction costs, however, frequently they are built with dedicated tracks within that right-of-way to prevent delays, especially where service densities have converged in the inner parts of the network. Most such trains run on the standard gauge track. Some light rail systems may run on a narrower gauge, some countries, including Finland, India, Pakistan, Russia, Brazil and Sri Lanka, as well as San Francisco in the USA and Melbourne and Adelaide in Australia, use broad gauge track. The fact that the terminology is not standardised across countries further complicates matters, most S-bahns typically behave like commuter rail with most trackage not separated from other trains, and long lines with trains running between cities and suburbs rather than within a city. The distances between stations however, are usually short, in larger systems there is usually a high frequency metro-like central corridor in the city center where all the lines converge into. Typical examples of large city S-Bahns include Munich and Frankfurt, S-Bahns do also exist in some mid-size cities like Rostock and Magdeburg but behave more like typical commuter rail with lower frequencies and very little exclusive trackage. A similar network exists in Copenhagen called the S-tog, in Hamburg and Copenhagen, other, diesel driven trains, do continue where the S-Bahn ends. Regional rail usually provides rail services between towns and cities, rather than purely linking major population hubs in the way inter-city rail does, Regional rail operates outside major cities. Unlike Inter-city, it stops at most or all stations between cities and it provides a service between smaller communities along the line, and also connections with long-distance services at interchange stations located at junctions or at larger towns along the line. Alternative names are local train or stopping train, examples include the former BRs Regional Railways, Frances TER, Germanys DB Regio and South Koreas Tonggeun services

24.
InterCityExpress
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The Intercity-Express or ICE is a system of high-speed trains predominantly running in Germany and its surrounding countries. It is the highest service category offered by DB Fernverkehr and is the flagship of Deutsche Bahn, the brand name ICE is among the best-known in Germany, with a brand awareness close to 100%, according to DB. There are currently 259 trainsets in five different versions of the ICE vehicles in use, named ICE1, ICE2, ICE T, ICE3, the ICE3, including its variant models, is made by a consortium led by Bombardier and Siemens. Procurement of a version, ICx, began c. 2008, and was rebranded ICE4 in late 2015, introduction of the trains are expected from 2016. Apart from domestic use, the trains can also be seen in countries neighbouring Germany, there are, for example, ICE1 lines to Basel and Zurich. ICE3 trains also run to Liège and Brussels and at speeds to Amsterdam. On 10 June 2007, a new line between Paris and Frankfurt/Stuttgart was opened, jointly operated by ICE and TGV trains, ICE trains to London via the Channel Tunnel are planned for 2018. While ICE 3M trains operate the Paris-Frankfurt service, SNCFs TGV runs from Paris to Munich, German and Austrian ICE T trains run to Vienna. On 9 December 2007, the ICE TD was introduced on the service from Berlin via Hamburg to the Danish cities of Aarhus and Copenhagen. The Spanish railway operator RENFE also employs trains based on the ICE3 called AVE Class 103 which are certified to run at speeds up to 350 km/h. Wider versions were ordered by China for the Beijing–Tianjin Intercity Railway link and by Russia for the Moscow – Saint Petersburg, the Deutsche Bundesbahn started a series of trials in 1985 using the InterCityExperimental test train. The IC Experimental was used as a train and for high-speed trials. The train was retired in 1996 and replaced with a new trial unit, the order was extended to 60 units in 1990, with German reunification in mind. However, not all trains could be delivered in time, the ICE network was officially inaugurated on 29 May 1991 with several vehicles converging on the newly built station Kassel-Wilhelmshöhe from different directions. The first ICE trains were the trainsets of ICE1, which came into service in 1989, the Hanover-Würzburg line and the Mannheim-Stuttgart line, which had both opened the same year, were hence integrated into the ICE network from the very beginning. Due to the lack of trainsets in 1991 and early 1992, prior to that date, ICE trainsets were used when available and were integrated in the Intercity network and with IC tariffs. In 1993, the ICE line 6s terminus was moved from Hamburg to Berlin, from 1997, the successor, the ICE2 trains pulled by Class 402 powerheads, was put into service

25.
Acela
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The route contains segments of high-speed rail, and Acela Express trains are the fastest trainsets in the Americas, they attain 150 mph on 28 miles of the route. Acela trains use tilting technology, which helps control lateral centrifugal forces, over this route, Acela and the Northeast Regional line captured a 75% share of air/train commuters between New York and Washington in 2011, up from 37% in 2000. Due to this competition, one airline canceled service between Washington and New York, on other portions Acela is limited by both traffic and infrastructure. On the 231-mile section from Bostons South Station to New Yorks Penn Station, along this section, Acela has still captured 54% share of the combined train and air market. The entire 457-mile route from Boston to Washington takes 7 hours, Acela carried more than 3.4 million passengers in fiscal year 2015, second only to the slower and cheaper Northeast Regional, which had over 8 million passengers in FY2015. Its 2015 revenue of $585 million was 25% of Amtraks total, the present Acela Express equipment will be replaced by new Avelia Liberty trainsets beginning in 2021, with all current trains to retire by the end of 2022. The new trainsets, manufactured by Alstom, will have 30% higher seating capacity than the current trains, the new fleet will have 28 trains versus the current 20, allowing for hourly New York-Boston service all day and half-hourly New York-Washington service at peak hours. During the 1980s the US Federal Railroad Administration explored the possibilities of high-speed rail in the United States, on December 18,1991, five potential high speed rail corridors were authorized including the Northeast Corridor. Amtrak asked railway equipment manufacturers to submit proposals, an X2000 train was leased from Sweden for test runs from October 1992 to January 1993. It was operated from Washington DC to New York City from February to May, Siemens showed the ICE1 train from Germany, organizing the ICE Train North America Tour which started to operate on the Northeast Corridor on July 3,1993. This testing allowed Amtrak to define a set of specifications that went into a tender in October 1994. On March 9,1999, Amtrak unveiled its plan for a high-speed train, twenty new trains were to run on the Northeast Corridor. Several changes were made to the corridor to make it suitable for the Acela, in October 1994, Amtrak requested bids from train manufacturers for a trainset that could reach 150 miles per hour. A joint project of Bombardier and GEC Alsthom was selected in March 1996, an inaugural VIP run of the Acela came on November 17,2000 followed by the first revenue run on December 11, a few months after the intended date. By 2005, Amtraks share of the market between New York and Boston had reached 40%, from 18% pre-Acela. With the increasing popularity of the faster, modern Acela Express, to meet the demand, more Acela services were added in September 2005. By August 2008 crowding had become noticeable, by 2011, the Acela fleet had reached half of its designed service life. Amtrak proposed several replacement options, including one as part of its A Vision for High-Speed Rail in the Northeast Corridor, in 2011, Amtrak announced that forty new Acela coaches would be ordered in 2012 to increase capacity on existing trainsets

26.
Shinkansen
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The Shinkansen is a network of high-speed railway lines in Japan operated by five Japan Railways Group companies. The nickname bullet train is used in English for these high-speed trains. The maximum operating speed is 320 km/h, test runs have reached 443 km/h for conventional rail in 1996, and up to a world record 603 km/h for maglev trains in April 2015. Shinkansen literally means new trunk line, referring to the rail line network. The name Superexpress, initially used for Hikari trains, was retired in 1972 but is used in English-language announcements. The original Tōkaidō Shinkansen, connecting the largest cities of Tokyo, carrying 151 million passengers per year, and at over 5 billion total passengers it has transported more passengers than any other high-speed line in the world. The service on the line operates much larger trains and at higher frequency than most other high speed lines in the world. At peak times, the line carries up to thirteen trains per hour in direction with sixteen cars each with a minimum headway of three minutes between trains. While the Shinkansen network has been expanding, Japans declining population is expected to cause ridership to decline over time, the recent expansion in tourism has boosted ridership marginally. Japan was the first country to build dedicated railway lines for high-speed travel, because of the mountainous terrain, the existing network consisted of 1,067 mm narrow-gauge lines, which generally took indirect routes and could not be adapted to higher speeds. Consequently, Japan had a greater need for new high-speed lines than countries where the standard gauge or broad gauge rail system had more upgrade potential. Other significant people responsible for its development were Tadanao Miki, Tadashi Matsudaira. They were responsible for much of the development of the first line. All three had worked on aircraft design during World War II, the popular English name bullet train is a literal translation of the Japanese term dangan ressha, a nickname given to the project while it was initially being discussed in the 1930s. The name stuck because of the original 0 Series Shinkansens resemblance to a bullet and these plans were abandoned in 1943 as Japans position in World War II worsened. However, some construction did commence on the line, several tunnels on the present-day Shinkansen date to the war-era project, by the mid-1950s the Tōkaidō Line was operating at full capacity, and the Ministry of Railways decided to revisit the Shinkansen project. In 1957, Odakyu Electric Railway introduced its 3000 series SE Romancecar train and this train gave designers the confidence that they could safely build an even faster standard gauge train. Thus the first Shinkansen, the 0 series, was built on the success of the Romancecar, in the 1950s, the Japanese national attitude was that railways would soon be outdated and replaced by air travel and highways as in America and many countries in Europe

27.
China Railway High-speed
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China Railway High-speed is the high-speed rail service operated by China Railway. Hexie Hao is the designation for rolling stock operated for this service, All trains had been marked CRH, before being changed shortly afterwards to the Chinese characters 和谐号 on the centre of the head vehicles and the side of the walls of other vehicles. The introduction of CRH was a part of the sixth national railway speedup. All high-speed trains in use in China are named CRH. CRH1/2A/2B/2E/5 are expected to have a speed of 250 km/h. The new trainsets CRH380A have a maximum test speed of 416.6 km/h, the fastest trainset, CRH380BL, attained a maximum test speed of 487.3 km/h 302.8 mph). High-speed rail services were first introduced in 2007 operating with CRH rolling stock and those run on existing lines that have been upgraded to speeds of up to 250 km/h and on newer dedicated high-speed track rated up to 350 km/h. China Railway High-speed runs different electric multiple unit trainsets, the designs for which are imported from other nations and designated CRH-1 through CRH-5 and CRH380A, CRH380B, CRH trainsets are intended to provide fast and convenient travel between cities. Some of the trainsets are manufactured locally through technology transfer, a key requirement for China, the signalling, track and support structures, control software, and station design are developed domestically with foreign elements as well, so the system as a whole is predominantly Chinese. China currently holds many new patents related to the components of these trains. However, these patents are valid within China, and as such hold no international power. An order for 60 8-car sets had been placed in 2004, with the first few built in Japan and it is designed to have two versions, one with a top operating speed of 220 km/h, the other with a top operating speed of 160 km/h. They will be used on 200 km/h or 250 km/h Inter-city High Speed Rail lines, planned to service by 2011 CRH380A. CRH3C and CRH2C designs have an MOR of 300 km/h, and can reach up to 350 km/h, however, in practical terms, issues such as maintenance costs, comfort, and safety make the maximum speed of more than 380 km/h impractical and remain limiting factors. Based on data published by Sinolink Securities, some changes were made according to the most recent news. ^1 All CRH380B and CRH380C units to be delivered before 2012, ^2 All CRH380D units to be delivered before 2014. Before the introduction of technology, China conducted independent attempts to domestically develop high-speed rail technology. Some notable results included the China Star, but domestic Chinese companies lacked the technology and expertise of foreign companies, if using only their own resources and expertise, the country might need a decade or longer to catch up with developed nations

28.
TGV
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TGV is Frances intercity high-speed rail service, operated by SNCF, the national rail operator. It was developed in the 1970s by GEC-Alsthom and SNCF, originally designed as turbotrains to be powered by gas turbines, the prototypes evolved into electric trains with the 1973 oil crisis. A TGV test train set the record for the fastest wheeled train, in mid-2011, scheduled TGV trains operated at the highest speeds in conventional train service in the world, regularly reaching 320 km/h on the LGV Est, LGV Rhin-Rhône, and LGV Méditerranée. The commercial success of the first LGV, the LGV Sud-Est, led to an expansion of the network to the south, and new lines in the west, north, and east. Eager to emulate the TGVs success, neighbouring countries Italy, Spain, Several future lines are planned, including extensions within France and to surrounding countries. Cities such as Tours have become part of a TGV commuter belt around Paris, in 2007, SNCF generated profits of €1.1 billion driven largely by higher margins on the TGV network. The idea of the TGV was first proposed in the 1960s, at the time the French government favoured new technology, exploring the production of hovercraft and the Aérotrain air-cushion vehicle. Simultaneously, SNCF began researching high-speed trains on conventional tracks, in 1976, the government agreed to fund the first line. By the mid-1990s, the trains were so popular that SNCF president Louis Gallois declared TGV The train that saved French railways, TGV001 was not a wasted prototype, its gas turbine was only one of its many new technologies for high-speed rail travel. It also tested high-speed brakes, needed to dissipate the large amount of energy of a train at high speed, high-speed aerodynamics. It was articulated, i. e. two adjacent carriages shared a bogie, allowing free yet controlled motion with respect to one another and it reached 318 km/h, which remains the world speed record for a non-electric train. Its interior and exterior were styled by British-born designer Jack Cooper, whose work formed the basis of early TGV designs, changing the TGV to electric traction required a significant design overhaul. The first electric prototype, nicknamed Zébulon, was completed in 1974, testing such as innovative body mounting of motors, pantographs, suspension. Body mounting of motors allowed over 3 tonnes to be eliminated from the power cars, the prototype travelled almost 1,000,000 km during testing. In 1976 the French government funded the TGV project, and construction of the LGV Sud-Est, the line was given the designation LN1, Ligne Nouvelle 1. After two pre-production trainsets had been tested and substantially modified, the first production version was delivered on 25 April 1980, the LGV opened to the public between Paris and Lyon on 27 September 1981. Contrary to its earlier fast services, SNCF intended TGV service for all types of passengers and this commitment to a democratised TGV service was enhanced in the Mitterrand era with the promotional slogan Progress means nothing unless it is shared by all. The TGV was considerably faster than normal trains, cars, or aeroplanes, the trains became widely popular, the public welcoming fast and practical travel

29.
Regenerative braking
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A regenerative brake is an energy recovery mechanism which slows a vehicle or object by converting its kinetic energy into a form which can be either used immediately or stored until needed. This contrasts with conventional braking systems, where the kinetic energy is converted to unwanted and wasted heat by friction in the brakes. In addition to improving the efficiency of the vehicle, regeneration can greatly extend the life of the braking system as its parts do not wear as quickly. The most common form of regenerative brake involves a motor as an electric generator. In electric railways the electricity generated is fed back into the supply system, in battery electric and hybrid electric vehicles, the energy is stored chemically in a battery, electrically in a bank of capacitors, or mechanically in a rotating flywheel. Hydraulic hybrid vehicles use hydraulic motors to store energy in the form of compressed air, the regenerative braking effect drops off at lower speeds, and cannot bring a vehicle to a complete halt reasonably quickly. A regenerative brake does not immobilise a vehicle, physical locking is required. Many road vehicles with regenerative braking do not have drive motors on all wheels, for safety, the ability to brake all wheels is required. The regenerative braking effect available is limited, and insufficient in many cases, the friction brake is a necessary back-up in the event of failure of the regenerative brake. Regenerative and friction braking must both be used, creating the need to them to produce the required total braking. The GM EV-1 was the first commercial car to do this, in 1997 and 1998 engineers Abraham Farag and Loren Majersik were issued two patents for this brake-by-wire technology. Electric motors, when used in function as generators, convert mechanical energy into electrical energy. Vehicles propelled by electric motors use them as generators when using regenerative braking, braking by transferring energy from the wheels to an electrical load. Early examples of this system were the front-wheel drive conversions of horse-drawn cabs by Louis Antoine Krieger in Paris in the 1890s, the Krieger electric landaulet had a drive motor in each front wheel with a second set of parallel windings for regenerative braking. These included tramway systems at Devonport, Rawtenstall, Birmingham, Crystal Palace-Croydon, slowing the speed of the cars or keeping it in control on descending gradients, the motors worked as generators and braked the vehicles. The tram cars also had brakes and track slipper brakes which could stop the tram should the electric braking systems fail. In several cases the car motors were shunt wound instead of series wound. Following a serious accident at Rawtenstall, an embargo was placed on this form of traction in 1911, Regenerative braking has been in extensive use on railways for many decades

30.
Kinetic energy
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In physics, the kinetic energy of an object is the energy that it possesses due to its motion. It is defined as the work needed to accelerate a body of a mass from rest to its stated velocity. Having gained this energy during its acceleration, the body maintains this kinetic energy unless its speed changes, the same amount of work is done by the body in decelerating from its current speed to a state of rest. In classical mechanics, the energy of a non-rotating object of mass m traveling at a speed v is 12 m v 2. In relativistic mechanics, this is an approximation only when v is much less than the speed of light. The standard unit of energy is the joule. The adjective kinetic has its roots in the Greek word κίνησις kinesis, the dichotomy between kinetic energy and potential energy can be traced back to Aristotles concepts of actuality and potentiality. The principle in classical mechanics that E ∝ mv2 was first developed by Gottfried Leibniz and Johann Bernoulli, Willem s Gravesande of the Netherlands provided experimental evidence of this relationship. By dropping weights from different heights into a block of clay, Émilie du Châtelet recognized the implications of the experiment and published an explanation. The terms kinetic energy and work in their present scientific meanings date back to the mid-19th century, early understandings of these ideas can be attributed to Gaspard-Gustave Coriolis, who in 1829 published the paper titled Du Calcul de lEffet des Machines outlining the mathematics of kinetic energy. William Thomson, later Lord Kelvin, is given the credit for coining the term kinetic energy c, energy occurs in many forms, including chemical energy, thermal energy, electromagnetic radiation, gravitational energy, electric energy, elastic energy, nuclear energy, and rest energy. These can be categorized in two classes, potential energy and kinetic energy. Kinetic energy is the movement energy of an object, Kinetic energy can be transferred between objects and transformed into other kinds of energy. Kinetic energy may be best understood by examples that demonstrate how it is transformed to, for example, a cyclist uses chemical energy provided by food to accelerate a bicycle to a chosen speed. On a level surface, this speed can be maintained without further work, except to overcome air resistance, the chemical energy has been converted into kinetic energy, the energy of motion, but the process is not completely efficient and produces heat within the cyclist. The kinetic energy in the moving cyclist and the bicycle can be converted to other forms, for example, the cyclist could encounter a hill just high enough to coast up, so that the bicycle comes to a complete halt at the top. The kinetic energy has now largely converted to gravitational potential energy that can be released by freewheeling down the other side of the hill. Since the bicycle lost some of its energy to friction, it never regains all of its speed without additional pedaling, the energy is not destroyed, it has only been converted to another form by friction

31.
Baltimore Belt Line
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It included the Howard Street Tunnel, the Mount Royal Station and the first mainline railroad electrification in the United States. The line is operated by CSX Transportation as part of its Baltimore Terminal Subdivision. In 1884, the PW&B was purchased by the Pennsylvania Railroad, a rival of the B&O. The B&O then proceeded to build its Philadelphia Branch to connect to the Philadelphia and Reading Railroad, the combination also provided a connection to the Staten Island Railway, which served as the terminal switching company for the B&Os New York freight service. Connecting the new Philadelphia Branch to the rest of the B&O system was an engineering challenge. A new surface line across the center of town was politically impossible, building around the outskirts of town would have required massive regrading and bridging, as the terrain is extremely hilly and the line would cut across every watershed flowing into the harbor. As a temporary expedient, traffic was handled through Baltimore on carfloats, the route the B&O chose started from the existing end of track at Camden station, at the west end of the Inner Harbor. A tunnel was constructed directly under Howard Street, heading north until just before it crossed the existing PRR line, at the north portal of the tunnel, Mount Royal Station was constructed. The cost of construction drove the railroad into bankruptcy shortly after the line opened in 1895, lower-level platforms were added at the east end of B&Os Camden Station in 1897. The Howard Street Tunnel, originally a 1. 4-mile long tunnel under Howard Street in downtown Baltimore, took four, the tunnel is brick-lined with iron-arched centerings. At the time of completion it was considered innovative for its use of electricity for illumination, inside the tunnel, there was an underground platform for trains serving Camden Station. The Howard Street Tunnel is listed on the National Register of Historic Places, by this time the Pennsylvania Railroad line through Baltimore and points south had been in operation for twenty years. Due to the nature of the area traversed and the hilly terrain, much of its line through town was in tunnels. Large chimneys were constructed above the Pennsylvania line, in a not entirely successful attempt to disperse the fumes from the coal-fired locomotives. This equipment was delivered beginning in 1895, and the first train pulled by a locomotive operated through the Howard Street Tunnel on June 27,1895. The grade on the portion was downhill to Camden Station, therefore traffic heading southbound, from Mount Royal Station. Since the engine was not working, the produced was relatively light. When northbound passenger trains stopped at Mt. Royal Station at the end of the tunnel

32.
Pantograph (rail)
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A pantograph is an apparatus mounted on the roof of an electric train, tram or electric bus to collect power through contact with an overhead catenary wire. It is a type of current collector. Typically, a wire is used, with the return current running through the track. The term stems from the resemblance of some styles to the mechanical pantographs used for copying handwriting, the pantograph was invented in 1879 by Walter Reichel, chief engineer at Siemens & Halske in Germany. A flat slide-pantograph was invented in 1895 at the Baltimore and Ohio Railroad The familiar diamond-shaped roller pantograph was invented by John Q. Brown of the Key System shops for their commuter trains ran between San Francisco and the East Bay section of the San Francisco Bay Area in California. They appear in photographs of the first day of service,26 October 1903, for many decades thereafter, the same diamond shape was used by electric-rail systems around the world and remains in use by some today. The most common type of today is the so-called half-pantograph. Louis Faiveley invented this type of pantograph in 1955, the half-pantograph can be seen in use on everything from very fast trains to low-speed urban tram systems. The electric transmission system for electric rail systems consists of an upper. The pantograph is spring-loaded and pushes a contact shoe up against the underside of the wire to draw the current needed to run the train. The steel rails of the act as the electrical return. As the train moves, the shoe slides along the wire and can set up standing waves in the wires which break the contact. This means that on some systems adjacent pantographs are not permitted, pantographs are the successor technology to trolley poles, which were widely used on early streetcar systems. However, many of these networks, including Torontos, are undergoing upgrades to accommodate pantograph operation, as a precaution against loss of pressure in the second case, the arm is held in the down position by a catch. For high-voltage systems, the air supply is used to blow out the electric arc when roof-mounted circuit breakers are used. Pantographs may have either a single or a double arm, double-arm pantographs are usually heavier, requiring more power to raise and lower, but may also be more fault-tolerant. On railways of the former USSR, the most widely used pantographs are those with a double arm, some streetcars use double-arm pantographs, among them the Russian KTM-5, KTM-8, LVS-86 and many other Russian-made trams, as well as some Euro-PCC trams in Belgium

33.
Alco-GE
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Alco-GE was a partnership between the American Locomotive Company and General Electric that lasted from 1940 to 1953. Under this arrangement, Alco produced the body and prime mover. Alco management could see that the market for steam locomotives would soon vanish, notable locomotives produced by Alco-GE were the RS-1, the first road switcher, and UP50, a prototype gas turbine-electric locomotive. GE later dissolved the partnership and decided to build their own locomotives, Alco still received electrical gear from GE, but was no longer GEs sole customer for such parts. The first diesel road locomotives GE built were two A-B sets, later called the UM20, GEs first production domestic road locomotive was the U25

34.
NYC S-Motor
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S-Motor was the class designation given by the New York Central to its ALCO-GE built S-1, S-2, S-2a and S-3 electric locomotives. The S-Motors hold the distinction of being the worlds first mass-produced main line locomotives with the prototype #6000 being constructed in 1904. The S-Motors would serve alone until the more powerful T-motors began to arrive in 1913, from that point the class was assigned to shorter commuter trains and deadhead rolling stock between Grand Central Terminal and Mott Haven coach yard. After a disastrous 1903 accident in the Park Avenue Tunnel the New York legislature passed a law banning steam locomotives within the city limits effective in 1908. Seeing an opportunity, the railroad decided this could mean a chance to rebuild its congested Midtown Manhattan stub end terminal. The initial prototype locomotive, delivered as Class L #6000, was in the 1-D-1 configuration with 4 gearless bi-polar type traction motors used the axle shaft as the motor armature. Between October 1904 and July 1906 #6000 racked up 50,000 miles in test on a track near both Alco and GE plants in Schenectady, New York, the advantages of the new locomotive were striking. It was only half the length of a steam locomotive with tender. The locomotive required no turntable and could be reversed for service in the direction in a matter of seconds. With the tests complete an order was placed for 34 additional locomotives to be delivered in the 3400 series and classed T-2 with the original being re-classed T-1. Unfortunately, two days into the new service in 1907 a train led by two T-2 class locomotives number 3407 and 3421 derailed on a curve on the Harlem Line killing 24. The investigation identified design flaws involving the long wheelbase and its performance at high speed. The solution was to convert the class to use 2 axle leading and trailing trucks to better guide the locomotive around curves. Units already delivered were modified to fit the wheels and units not delivered were modified in the factory. Again the class was changed from T to S, finally in 1908 an additional batch of 12 locomotives, class S-3, were ordered to support the electrification being extended to White Plains, NY on the Harlem Line. With weight split between powered and unpowered axles the S motors were never completely satisfactory at pulling long heavy trains at high speed, the 1907 accident only made matters worse with additional unpowered axles being added and new speed restrictions imposed. Finally in 1913 the new class of T-Motors arrived, displacing the S Motors from first line service, for the next 60 years the S-motors were assigned to short local commuter trains and empty equipment movements between Grand Central and the Coach Yards at Mott Haven. They were later re-numbered into the 1100 series and ultimately the 100 series with some examples surviving the Penn Central merger and their final assignment was switching service in the underground yards of Grand Central Terminal

35.
Milwaukee Road class ES-2
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The Milwaukee Roads class ES-2 comprised four electric switcher locomotives. Two were built in 1916 and the two in 1919. They were of steeplecab design, with a single roof-mounted pantograph to access the Milwaukees 3,000 V DC overhead line, originally numbered 10050–10053, they were renumbered E80–E83 in March 1939. The ES-2 was the Milwaukee Roads primary class of dedicated electric switchers, electric switching on the Milwaukee Road was always limited to the Rocky Mountain Division, and to the middle and east end only, Avery being merely a power change, rather than a switching, location. Despite their highly specialized niche on the Milwaukee Road, the ES-2s were well-liked by personnel, engineers liked them due to their rapid throttle response, preferring them over diesels which were slower to transition and accelerate. Their simple nature made them easy to service, and the units seldom needed major attention, few changes were made to them over the years, the most important of which was the addition of extra steel plates, which added weight and reduced wheelslip. For this reason, the pole was tipped with a plate rather than a shoe or trolley wheel. From 1951 to 1974, one ES-2 was the Deer Lodge switcher, one unit was held in reserve at Deer Lodge to substitute for either of the other two. The E83 became surplus and was scrapped in 1952, the other three continued in service until the end of electric operations on the Milwaukee Road on June 15,1974. The E82 was also the last Milwaukee electric locomotive to operate on the final day, media related to Milwaukee Road class ES-2 locomotives at Wikimedia Commons

36.
Steeplecab
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In railroad terminology, a steeplecab is a style or design of electric locomotive, the term is rarely if ever used for other forms of power. The name originated in North America and has used in Britain as well as the alternative camelback. A steeplecab design has a driving cab area which may include a full-height area in between for electrical equipment. On both ends, connected to the full-height cab areas, lower noses contain other equipment, especially noisy equipment such as air compressors not desired within the cab area.001. In 1902, the British North Eastern Railway placed an order for two locomotives of virtually identical design, the ES1. These locomotives started work in 1905 and were retired in 1964. The steeplecab design was popular for electric switcher locomotives, and on electric locomotives ordered for interurban. It offers a degree of crash protection for the crew combined with good visibility. Disadvantages include reduced room for electrical equipment compared to other designs. The first two members of the Victorian Railways E class electric locomotives, introduced in 1923, were of a steeplecab design, the Compagnie du chemin de fer de Paris à Orléans introduced eight steeplecab locomotives derived from a General Electric design for the Baltimore Belt Line in 1900. A single locomotive was built in 1900 by Thomson-Houston and General Electric for the Milan & Varese railway, the Hungarian designer Kálmán Kandó was employed by the Ganz works to electrify the Italian Valtellina railway, Milan, his steeplecab locomotive was operational in 1901. When the Central London Railway opened in 1900, its trains were hauled by electric locomotives. Due to severe vibrations as a result of their most of their weight being unsprung, they were withdrawn in 1903, the North Eastern Railway operated three classes of camelbacks between 1905 and the companys merger under Grouping in 1922. These became, British Rail Class EE1 British Rail Class EF1 British Rail Class ES1 The Lancashire and Yorkshire Railway also built at least two steeplecab locomotives, one was a straight electric which could pick up current from third rail or overhead wire. In the US, several examples of electric locomotives can be found preserved at various railway museums. At least one common carrier railroad, the Iowa Traction, still operates several locomotives of this style, the Western Railway Museum features two former Sacramento Northern locomotives in its collection, both built by General Electric. The New York Transit Museum has three preserved South Brooklyn Railway steeplecab locomotives in its collection, at least one of which operated on fan trips during the centennial in 2004

37.
Switcher
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They do this in classification yards. Switchers may also make short runs and even be the only motive power on branch lines and switching. The term can also be used to describe the workers operating these engines or engaged in directing shunting operations, the typical switcher is optimised for its job, being relatively low-powered but with a high starting tractive effort for getting heavy cars rolling quickly. Switchers are geared to produce high torque but are restricted to low top speeds and have small diameter driving wheels, switchers are rail analogs to tugboats. US switchers tend to be larger, with bogies to allow them to be used on tight radiuses, European shunters tend to be smaller and more often have fixed axles. They also often maintained coupling rods for longer than other types, although bogie types have long been used where very heavy loads are involved. Switching is hard work, and heavily used switch engines wear out quickly from the abuse of constant hard contacts with cars, nevertheless, some types have been remarkably long-lived. Diesel switchers tend to have a cab and often lower and/or narrower hoods containing the diesel engines. Slugs are often used because they allow even greater effort to be applied. Nearly all slugs used for switching are of the low hood, good visibility in both directions is critical, because a switcher may be running in either direction, turning the locomotive is time-consuming. Some earlier diesel switchers used cow-calf configurations of two powered units in order to provide greater power, the vast majority of modern switchers are diesels, but countries with near-total electrification, like Switzerland, use electric switchers. Prior to the introduction of locomotives, electric shunting locomotives were used to an extent in Great Britain where heavy trains needed to be started on steep gradients. The steeply-graded Quayside Branch in Newcastle upon Tyne was electrified by the North Eastern Railway in 1905,1, is now part of the National Collection and resides at Locomotion in Shildon. A number of the early German locomotives built for use on lines have been preserved. These specialised locomotives were tall steeple-cab types not seen anywhere else, one example built by Greenwood and Batley in Armley, Leeds is preserved at the Middleton Railway, not far from where it was built. Small industrial shunters are sometimes of the battery-electric type, an early battery-electric shunting locomotive is shown here. The Tyne and Wear Metro has three battery electric shunters built by Hunslet, which are used to haul engineering trains when the supply is switched off. Flywheel energy storage was used experimentally by Sentinel

38.
Aberdeen
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Nicknames include the Granite City, the Grey City and the Silver City with the Golden Sands. During the mid-18th to mid-20th centuries, Aberdeens buildings incorporated locally quarried grey granite, since the discovery of North Sea oil in the 1970s, other nicknames have been the Oil Capital of the World or the Energy Capital of the World. The area around Aberdeen has been settled since at least 8,000 years ago, the city has a long, sandy coastline and a marine climate, the latter resulting in chilly summers and mild winters. Aberdeen received Royal Burgh status from David I of Scotland, transforming the city economically, the traditional industries of fishing, paper-making, shipbuilding, and textiles have been overtaken by the oil industry and Aberdeens seaport. Aberdeen Heliport is one of the busiest commercial heliports in the world, in 2015, Mercer named Aberdeen the 57th most liveable city in the world, as well as the fourth most liveable city in Britain. In 2012, HSBC named Aberdeen as a business hub and one of eight super cities spearheading the UKs economy. The Aberdeen area has seen human settlement for at least 8,000 years. The city began as two separate burghs, Old Aberdeen at the mouth of the river Don, and New Aberdeen, a fishing and trading settlement, the earliest charter was granted by William the Lion in 1179 and confirmed the corporate rights granted by David I. In 1319, the Great Charter of Robert the Bruce transformed Aberdeen into a property-owning, granted with it was the nearby Forest of Stocket, whose income formed the basis for the citys Common Good Fund which still benefits Aberdonians. The city was burned by Edward III of England in 1336, but was rebuilt and extended, the city was strongly fortified to prevent attacks by neighbouring lords, but the gates were removed by 1770. During the Wars of the Three Kingdoms of 1644–1647 the city was plundered by both sides, in 1644, it was taken and ransacked by Royalist troops after the Battle of Aberdeen and two years later it was stormed by a Royalist force under the command of Marquis of Huntly. In 1647 an outbreak of plague killed a quarter of the population. In the 18th century, a new Town Hall was built and the first social services appeared with the Infirmary at Woolmanhill in 1742 and the Lunatic Asylum in 1779. The council began major road improvements at the end of the 18th century with the main thoroughfares of George Street, King Street, gas street lighting arrived in 1824 and an enhanced water supply appeared in 1830 when water was pumped from the Dee to a reservoir in Union Place. An underground sewer system replaced open sewers in 1865, the city was incorporated in 1891. Although Old Aberdeen has a history and still holds its ancient charter. It is an part of the city, as is Woodside. Old Aberdeen is the location of Aberdon, the first settlement of Aberdeen

39.
Galvanic cell
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It generally consists of two different metals connected by a salt bridge, or individual half-cells separated by a porous membrane. Volta was the inventor of the pile, the first electrical battery. In common usage, the battery has come to include a single galvanic cell. In 1780, Luigi Galvani discovered that two different metals are connected and then both touched at the same time to two different parts of a nerve of a frog leg, then the leg contracts. The voltaic pile, invented by Alessandro Volta in the 1800s, however, Volta built it entirely out of non-biological material in order to challenge Galvanis animal electricity theory in favour of his own metal-metal contact electricity theory. Carlo Matteucci in his turn constructed a battery out of biological material in answer to Volta. These discoveries paved the way for electrical batteries, Voltas cell was named an IEEE Milestone in 1999 and it was suggested by Wilhelm König in 1940 that the object known as the Baghdad battery might represent galvanic cell technology from ancient Parthia. Replicas filled with acid or grape juice have been shown to produce a voltage. However, it is far from certain that this was its purpose—other scholars have pointed out that it is similar to vessels known to have been used for storing parchment scrolls. In its simplest form, a half-cell consists of a metal that is submerged in a solution. This reduction reaction causes the electrons throughout the metal-B electrode, the wire. By definition, The anode is the electrode where oxidation takes place, in a cell, it is the negative electrode, as when oxidation occurs. These electrons then migrate to the cathode, however, in electrolysis, an electric current stimulates electron flow in the opposite direction. Thus, the anode is positive, and the statement anode attracts anions is true, the metal-A electrode is the anode. Instead, there is a tendency for aqueous ions to be reduced by the incoming electrons from the anode. However, in electrolysis, the cathode is the negative terminal, in this situation, the statement the cathode attracts cations is true. The metal-B electrode is the cathode, copper readily oxidizes zinc, for the Daniell cell depicted in the figure, the anode is zinc and the cathode is copper, and the anions in the solutions are sulfates of the respective metals. When an electrically conducting device connects the electrodes, the reaction is, Zn + Cu2+ → Zn2++ Cu The zinc electrode is dissolved

40.
Reluctance motor
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A reluctance motor is a type of electric motor that induces non-permanent magnetic poles on the ferromagnetic rotor. The rotor does not have any windings, torque is generated through the phenomenon of magnetic reluctance. There are various types of motors, Synchronous reluctance Variable reluctance Switched reluctance Variable reluctance stepping. Reluctance motors can deliver high power density at low cost. Disadvantages are high torque ripple when operated at low speed, until the early twenty-first century their use was limited by the complexity of designing and controlling them. Before the development of integrated circuits the control electronics would have been prohibitively costly. The stator consists of multiple projecting electromagnet poles, similar to a wound field brushed DC motor, the rotor consists of soft magnetic material, such as laminated silicon steel, which has multiple projections acting as salient magnetic poles through magnetic reluctance. When a rotor pole is equidistant from the two adjacent stator poles, the pole is said to be in the fully unaligned position. This is the position of magnetic reluctance for the rotor pole. In the aligned position, two poles are fully aligned with two stator poles, and is a position of minimum reluctance. When a stator pole is energized, the torque is in the direction that will reduce reluctance. Thus the nearest rotor pole is pulled from the position into alignment with the stator field. In order to sustain rotation, the field must rotate in advance of the rotor poles. Some motor variants will run on 3-phase AC power, most modern designs are of the switched reluctance type, because electronic commutation gives significant control advantages for motor starting, speed control, and smooth operation. Dual-rotor layouts provide more torque at lower price per volume or per mass, the inductance of each phase winding in the motor will vary with position, because the reluctance also varies with position. This presents a control systems challenge, Synchronous reluctance motors have an equal number of stator and rotor poles. The projections on the rotor are arranged to introduce internal flux “barriers“, typical pole numbers are 4 and 6. As the rotor is operating at speed and there are no current-conducting parts in the rotor, rotor losses are minimal compared to those of an induction motor

41.
Commutator (electric)
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It consists of a cylinder composed of multiple metal contact segments on the rotating armature of the machine. The windings on the armature are connected to the commutator segments, Commutators are used in direct current machines, dynamos and many DC motors as well as universal motors. In a motor the commutator applies electric current to the windings, by reversing the current direction in the rotating windings each half turn, a steady rotating force is produced. The first direct current commutator-type machine, the dynamo, was built by Hippolyte Pixii in 1832, Commutators are relatively inefficient, and also require periodic maintenance such as brush replacement. Therefore, commutated machines are declining in use, being replaced by alternating current machines, a commutator consists of a set of contact bars fixed to the rotating shaft of a machine, and connected to the armature windings. As the shaft rotates, the commutator reverses the flow of current in a winding, for a single armature winding, when the shaft has made one-half complete turn, the winding is now connected so that current flows through it in the opposite of the initial direction. In a motor, the current causes the fixed magnetic field to exert a rotational force, or a torque. In a generator, the torque applied to the shaft maintains the motion of the armature winding through the stationary magnetic field. Practical commutators have at least three contact segments, to prevent a dead spot where two brushes simultaneously bridge only two commutator segments, Brushes are made wider than the insulated gap, to ensure that brushes are always in contact with an armature coil. With the remaining arms, a motor can produce sufficient torque to begin spinning the rotor. Two or more fixed brushes connect to the circuit, either a source of current for a motor or a load for a generator. Commutator segments are connected to the coils of the armature, with the number of depending on the speed. Large motors may have hundreds of segments, each conducting segment of the commutator is insulated from adjacent segments. Mica was used on machines and is still used on large machines. Many other insulating materials are used to smaller machines, plastics allow quick manufacture of an insulator, for example. The segments are held onto the shaft using a shape on the edges or underside of each segment. Insulating wedges around the perimeter of each segment are pressed so that the commutator maintains its mechanical stability throughout its operating range. In small appliance and tool motors the segments are typically crimped permanently in place, when the motor fails it is discarded and replaced

42.
Werner von Siemens
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Ernst Werner Siemens was a German inventor and industrialist. Siemens’s name has been adopted as the SI unit of electrical conductance and he was also the founder of the electrical and telecommunications company Siemens. He was a brother of Carl Heinrich von Siemens and Carl Wilhelm Siemens, sons of Christian Ferdinand Siemens, after finishing school, Siemens intended to study at the Bauakademie Berlin. Siemens was thought of as a soldier, receiving various medals, and inventing electrically-charged sea mines. Upon returning home from war, he put his mind to other uses and he is known world-wide for his advances in various technologies, and chose to work on perfecting technologies that had already been established. In 1843 he sold the rights to his first invention to Elkington of Birmingham, Siemens invented a telegraph that used a needle to point to the right letter, instead of using Morse code. Based on this invention, he founded the company Telegraphen-Bauanstalt von Siemens & Halske on 1 October 1847, the company was internationalised soon after its founding. One brother of Werner represented him in England and another in St. Petersburg, Russia, following his industrial career, he was ennobled in 1888, becoming Werner von Siemens. He retired from his company in 1890 and died in 1892 in Berlin, Siemens AG is one of the largest electrotechnological firms in the world. The von Siemens family still owns 6% of the shares and holds a seat on the supervisory board. Apart from the pointer telegraph Siemens made several contributions to the development of engineering and is therefore known as the founding father of the discipline in Germany. He built the worlds first electric elevator in 1880 and his company produced the tubes with which Wilhelm Conrad Röntgen investigated x-rays. He claimed invention of the dynamo although others invented it earlier, on 14 December 1877 he received German patent No.2355 for an electromechanical dynamic or moving-coil transducer, which was adapted by A. L. Thuras and E. C. Wente for the Bell System in the late 1920s for use as a loudspeaker, wentes adaptation was issued US patent 1,707,545 in 1929. Siemens is also the father of the trolleybus which he tried and tested with his Elektromote on 29 April 1882. He was married twice, first in 1852 to Mathilde Duman, patent 322,859 — Electric railway U. S. Patent 340,462 — Electric railway U. S, patent 415,577 — Electric meter U. S. Patent 428,290 — Electric meter U. S, patent 520,274 — Electric railway U. S. Werner von Siemens, Scientific & Technical Papers of Werner von Siemens

43.
Berlin
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Berlin is the capital and the largest city of Germany as well as one of its constituent 16 states. With a population of approximately 3.5 million, Berlin is the second most populous city proper, due to its location in the European Plain, Berlin is influenced by a temperate seasonal climate. Around one-third of the area is composed of forests, parks, gardens, rivers. Berlin in the 1920s was the third largest municipality in the world, following German reunification in 1990, Berlin once again became the capital of all-Germany. Berlin is a city of culture, politics, media. Its economy is based on high-tech firms and the sector, encompassing a diverse range of creative industries, research facilities, media corporations. Berlin serves as a hub for air and rail traffic and has a highly complex public transportation network. The metropolis is a popular tourist destination, significant industries also include IT, pharmaceuticals, biomedical engineering, clean tech, biotechnology, construction and electronics. Modern Berlin is home to world renowned universities, orchestras, museums and its urban setting has made it a sought-after location for international film productions. The city is known for its festivals, diverse architecture, nightlife, contemporary arts. Since 2000 Berlin has seen the emergence of a cosmopolitan entrepreneurial scene, the name Berlin has its roots in the language of West Slavic inhabitants of the area of todays Berlin, and may be related to the Old Polabian stem berl-/birl-. All German place names ending on -ow, -itz and -in, since the Ber- at the beginning sounds like the German word Bär, a bear appears in the coat of arms of the city. It is therefore a canting arm, the first written records of towns in the area of present-day Berlin date from the late 12th century. Spandau is first mentioned in 1197 and Köpenick in 1209, although these areas did not join Berlin until 1920, the central part of Berlin can be traced back to two towns. Cölln on the Fischerinsel is first mentioned in a 1237 document,1237 is considered the founding date of the city. The two towns over time formed close economic and social ties, and profited from the right on the two important trade routes Via Imperii and from Bruges to Novgorod. In 1307, they formed an alliance with a common external policy, in 1415 Frederick I became the elector of the Margraviate of Brandenburg, which he ruled until 1440. In 1443 Frederick II Irontooth started the construction of a new palace in the twin city Berlin-Cölln

44.
Gross-Lichterfelde Tramway
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The Gross Lichterfelde Tramway was the worlds first electric tramway. It was built by the Siemens & Halske company in Lichterfelde, a suburb of Berlin, werner von Siemens had presented the first electric passenger train at the Berlin industrial exhibition two years before. The 2.4 km long line started at Berlin-Lichterfelde Ost station on the Anhalt Railway line. Each car was equipped with a 180 Volt DC4 kW electric motor. Therefore, the 1,000 mm metre gauge tracks were separated from driveways. At railroad crossings the rails were dead or switched on only briefly before the approach of the tramcar, nevertheless, persons and horses frequently received electrical shocks. It is also believed that young persons caused short circuits which shut down the operation by putting wire mesh on the tracks, in 1891 the track was equipped with an overhead wire and the line was extended to Berlin-Lichterfelde West station. After several extensions, operation finally discontinued in 1931, Berlin tram Elektromote railserve. com, The First in Railroads and Trains The Railway News, Volume 56, Oct.10,1891, page 578 engagetechnology. com, History of transportation germaniatours. net Germany

45.
Volk's Electric Railway
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Volks Electric Railway is a narrow gauge heritage railway that runs along a length of the seafront of the English seaside resort of Brighton. It was built by Magnus Volk, the first section being completed in August 1883, although it was preceded by Werner von Siemenss 1879 demonstration line in Berlin and by the Gross-Lichterfelde Tramway of 1881, neither line is still operational. In 1883 Magnus Volk opened a short,2 ft electric railway running for 1⁄4 mile between Swimming Arch and Chain Pier, electrical power at 50 V DC was supplied to the small car using the two running rails. In 1884 the line was extended a further 1⁄2 mile beyond the Chain Pier to Paston Place, the electrical supply was increased to 160 V DC and the power plant was installed in the arch built into the cliff face at Paston Place. In 1886 an off-set third rail was added to minimise current leakage, in 1896 the unusual Brighton and Rottingdean Seashore Electric Railway was built by Volk. Due to problems concerning the construction of lengthened groynes to the east of Paston Place this fascinating railway closed in 1901, following the closure Volks original electric railway was extended from Paston Place to Black Rock. Paston Place was also the home of Volks Seaplane Station, which was used by Volks son George Herbert Volk, in 1930 the line was cut back 200 yards from Palace Pier to its present terminus, still known as Aquarium. In 1935 a lido was built at Black Rock, and the line was shortened by around 200 yards to accommodate it, in 1937 a new Black Rock station was opened at the end of the shortened line. In April 1940, Brighton Corporation took control of the line, only four months later, World War II defensive preparations caused the line to close. After the war, starting in 1947, the corporation rebuilt the line using 50 lb/yd rail for the line and 25 lb/yd mounted on insulators for the third rail. At Black Rock a new station was built to replace the 1937 building which had suffered badly during the war, the line reopened for passengers in 1948. Two-car multiple operation was introduced in 1964, in recent years there has been a decline in visitor numbers due to package holidays abroad. In 1995 the Volks Electric Railway Association was formed to help the operator of the line promote and operate the line. And in 2003 the Volks Railway Institute of Science and Technology was formed to promote the educational and science side of the Victorian railway to schools and special interest groups. In the late 1990s the Black Rock end of the line was shortened by 211 feet to permit a storm water storage scheme to be built in the marina area. The 1948 station was demolished and replaced by a new single platform station, in 2014 it was announced that the railway had been awarded a grant of £1.6 million by the Heritage Lottery Fund, a sum which must be spent by March 2017. Today the line runs between stations at Aquarium and Black Rock, with an intermediate station and depot at Paston Place. The line has a 2 ft 8 1⁄2 in narrow gauge, is electrified at 110 V DC using a third rail, the line is single throughout with a passing loop at Halfway Station

46.
Tram
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A tram is a rail vehicle which runs on tracks along public urban streets, and also sometimes on a segregated right of way. The lines or networks operated by tramcars are called tramways, Tramways powered by electricity, the most common type historically, were once called electric street railways. However, trams were used in urban areas before the universal adoption of electrification. Tram lines may run between cities and/or towns, and/or partially grade-separated even in the cities. Very occasionally, trams also carry freight, Tram vehicles are usually lighter and shorter than conventional trains and rapid transit trains, but the size of trams is rapidly increasing. Some trams may also run on railway tracks, a tramway may be upgraded to a light rail or a rapid transit line. For all these reasons, the differences between the modes of rail transportation are often indistinct. In the United States, the tram has sometimes been used for rubber-tired trackless trains. Today, most trams use electrical power, usually fed by a pantograph, in some cases by a sliding shoe on a third rail. If necessary, they may have dual power systems — electricity in city streets, trams are now included in the wider term light rail, which also includes segregated systems. The English terms tram and tramway are derived from the Scots word tram, referring respectively to a type of truck used in coal mines and the tracks on which they ran. The word tram probably derived from Middle Flemish trame, a Romanesque word meaning the beam or shaft of a barrow or sledge, the identical word la trame with the meaning crossbeam is also used in the French language. The word Tram-car is attested from 1873, although the terms tram and tramway have been adopted by many languages, they are not used universally in English, North Americans prefer streetcar, trolley, or trolleycar. The term streetcar is first recorded in 1840, and originally referred to horsecars, when electrification came, Americans began to speak of trolleycars or later, trolleys. The troller design frequently fell off the wires, and was replaced by other more reliable devices. The terms trolley pole and trolley wheel both derive from the troller, Modern trams often have an overhead pantograph mechanical linkage to connect to power, abandoning the trolley pole altogether. Conventional diesel tourist buses decorated to look like streetcars are sometimes called trolleys in the US, the term may also apply to an aerial ropeway, e. g. the Roosevelt Island Tramway. Over time, the trolley has fallen into informal use

Virgin Trains
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Virgin Trains is a train operating company in the United Kingdom owned by Virgin Rail Group and Stagecoach that has operated the InterCity West Coast franchise since 9 March 1997. Virgin Trains operates long-distance passenger services on the West Coast Main Line between London, West Midlands, North West England, North Wales and Scotland. The servi

2.
Pendolino 390001 Virgin Pioneer at Watford Junction

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Unidentified Class 221 Super Voyager at Llandudno Junction

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A map showing the off-peak service pattern each hour, as of 2015

British Rail Class 87
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The British Rail Class 87 is a type of electric locomotive built in 1973–75 by British Rail Engineering Limited. Thirty-six of these locomotives were built to passenger services over the West Coast Main Line. They were the flagships of British Rails electric locomotive fleet until the late 1980s, the privatisation of British Rail saw all but one of

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No.87030 "Black Douglas" in blue livery at Kenton in 1979.

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The unique Class 87/1, No.87101 Stephenson, in blue livery at Birmingham International station in 1988

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A Class 87 hauled express on the WCML in InterCity livery in 1994

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87025 'County of Cheshire' in 2002. One of the last Class 87s to be in service with Virgin Trains. The locomotive is painted in Virgin Trains' red and black livery.

Carlisle, Cumbria
–
Carlisle is a city and the county town of Cumbria. Historically in Cumberland, it is also the centre of the City of Carlisle district in North West England. Carlisle is located at the confluence of the rivers Eden, Caldew and it is the largest settlement in the county of Cumbria, and serves as the administrative centre for both Carlisle City Counci

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Aerial view of Carlisle City Centre

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General Gnaeus Julius Agricola advances through Carlisle in AD 79.

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Carlisle Castle was built in the reign of William the Second.

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Historic view of Carlisle

Locomotive
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A locomotive or engine is a rail transport vehicle that provides the motive power for a train. A locomotive has no payload capacity of its own, and its purpose is to move the train along the tracks. In contrast, some trains have self-propelled payload-carrying vehicles and these are not normally considered locomotives, and may be referred to as mul

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Three body styles of diesel locomotive: cab unit, hood unit and box cab. These locomotives are operated by Pacific National in Australia.

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R class steam locomotive number R707 as operated by the Victorian Railways of Australia.

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A Green Cargo RC 4 class electric locomotive repainted in its original livery for the Swedish 150-year railway anniversary in 2006.

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The first passenger railway, the Liverpool and Manchester Railway, in England.

Electricity
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Electricity is the set of physical phenomena associated with the presence of electric charge. Although initially considered a separate to magnetism, since the development of Maxwells Equations both are recognized as part of a single phenomenon, electromagnetism. Various common phenomena are related to electricity, including lightning, static electr

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Lightning is one of the most dramatic effects of electricity.

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Thales, the earliest known researcher into electricity

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Benjamin Franklin conducted extensive research on electricity in the 18th century, as documented by Joseph Priestley (1767) History and Present Status of Electricity, with whom Franklin carried on extended correspondence.

Overhead line
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An overhead line or overhead wire is used to transmit electrical energy to trams, trolleybuses, or trains. Overhead line is designed on the principle of one or more overhead wires situated over rail tracks, the feeder stations are usually fed from a high-voltage electrical grid. Electric trains that collect their current from overhead lines use a d

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Overhead lines on Swiss Federal Railways

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Overhead lines in China

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Overhead lines in Denmark near Roskilde. For aesthetic reasons the support structure is constructed from hollow Corten steel masts.

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Brussels-South, overhead wires suspended across multiple tracks.

Third rail
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A third rail is a method of providing electric power to a railway locomotive or train, through a semi-continuous rigid conductor placed alongside or between the rails of a railway track. It is used typically in a transit or rapid transit system. Third rail systems are supplied from direct current electricity. The third-rail system of electrificatio

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Third rail at the West Falls Church Metro station near Washington, D.C., electrified at 750 volts. The third rail is at the top of the image, with a white canopy above it. The two lower rails are the ordinary running rails; current from the third rail returns to the power station through these.

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A British Class 442 third-rail electric multiple unit in Battersea. This is the fastest class of third-rail EMU in the world, reaching 108 mph (174 km/h).

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Paris Metro. The guiding rails of the rubber-tyred lines are also current conductors. The horizontal current collector is between the pair of rubber wheels.

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London Stansted Airport people mover with central rail power feed

Battery (electricity)
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An electric battery is a device consisting of one or more electrochemical cells with external connections provided to power electrical devices such as flashlights, smartphones, and electric cars. When a battery is supplying power, its positive terminal is the cathode. The terminal marked negative is the source of electrons that when connected to a

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Various cells and batteries (top-left to bottom-right): two AA, one D, one handheld ham radio battery, two 9-volt (PP3), two AAA, one C, one camcorder battery, one cordless phone battery.

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A voltaic pile, the first battery

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From top to bottom: a large 4.5-volt (3R12) battery, a D Cell, a C cell, an AA cell, an AAA cell, an AAAA cell, an A23 battery, a 9-volt PP3 battery, and a pair of button cells (CR2032 and LR44).

4.
A device to check battery voltage

Fuel cell
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A fuel cell is a device that converts the chemical energy from a fuel into electricity through a chemical reaction of positively charged hydrogen ions with oxygen or another oxidizing agent. Fuel cells can produce electricity continuously for as long as these inputs are supplied, the first fuel cells were invented in 1838. The first commercial use

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Demonstration model of a direct-methanol fuel cell. The actual fuel cell stack is the layered cube shape in the center of the image

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Sketch of William Grove's 1839 fuel cell

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Condensation of water produced by a PEMFC on the air channel wall. The gold wire around the cell ensures the collection of electric current.

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Type 212 submarine with fuel cell propulsion of the German Navy in dry dock

Prime mover (locomotive)
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In engineering, a prime mover is an engine that converts fuel to useful work. In locomotives, the mover is thus the source of power for its propulsion. Generally it is any locomotive powered by a combustion engine. In an engine-generator set, the engine is the prime mover, in a diesel-mechanical locomotive, the prime mover is the diesel engine that

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Power unit (engine and generator right) from a diesel-electric locomotive

Diesel engine
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Diesel engines work by compressing only the air. This increases the air temperature inside the cylinder to such a degree that it ignites atomised diesel fuel that is injected into the combustion chamber. This contrasts with spark-ignition engines such as an engine or gas engine. In diesel engines, glow plugs may be used to aid starting in cold weat

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Diesel generator on an oil tanker

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A Diesel engine built by MAN AG in 1906

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A Hornsby-Akroyd oil engine working at the Great Dorset Steam Fair

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Diesel's original 1897 engine on display at the Deutsches Museum in Munich, Germany

Gas turbine
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A gas turbine, also called a combustion turbine, is a type of internal combustion engine. It has an upstream rotating compressor coupled to a turbine. The basic operation of the gas turbine is similar to that of the power plant except that the working fluid is air instead of water. Fresh atmospheric air flows through a compressor that brings it to

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GE H series power generation gas turbine: in combined cycle configuration, this 480- megawatt unit has a rated thermal efficiency of 60%.

Diesel-electric transmission
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Diesel-electric transmission, or diesel-electric powertrain is used by a number of vehicle and ship types for providing locomotion. A diesel-electric transmission system includes a diesel engine connected to an electrical generator, before diesel engines came into widespread use, a similar system, using a petrol engine and called petrol-electric or

Gas turbine-electric locomotive
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A gas turbine - electric locomotive, or GTEL, is a locomotive that uses a gas turbine to drive an electric generator or alternator. The electric current thus produced is used to power traction motors and this type of locomotive was first experimented with during the Second World War, but reached its peak in the 1950s to 1960s. Few locomotives use t

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UP 18, preserved at the Illinois Railway Museum.

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British Rail APT-E

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GT1-001

Transmission (mechanics)
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A transmission is a machine in a power transmission system, which provides controlled application of the power. Often the term refers simply to the gearbox that uses gears and gear trains to provide speed. In British English, the term refers to the whole drivetrain, including clutch, gearbox, prop shaft, differential. In American English, however,

Electric motor
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An electric motor is an electrical machine that converts electrical energy into mechanical energy. The reverse of this is the conversion of energy into electrical energy and is done by an electric generator. In normal motoring mode, most electric motors operate through the interaction between an electric motors magnetic field and winding currents t

Renewable energy
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Renewable energy is energy that is collected from renewable resources, which are naturally replenished on a human timescale, such as sunlight, wind, rain, tides, waves, and geothermal heat. Renewable energy often provides energy in four important areas, electricity generation, air and water heating/cooling, transportation, based on REN21s 2016 repo

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Wind, solar, and biomass are three emerging renewable sources of energy.

Geothermal power
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Geothermal power is power generated by geothermal energy. Technologies in use include dry steam power stations, flash steam power stations, Geothermal electricity generation is currently used in 24 countries, while geothermal heating is in use in 70 countries. As of 2015, worldwide geothermal power capacity amounts to 12.8 gigawatts, International

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Krafla, a geothermal power station in Iceland

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Larderello Geothermal Station, in Italy

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A geothermal power station in Negros Oriental, Philippines.

Hydroelectricity
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Hydroelectricity is electricity produced from hydropower. In 2015 hydropower generated 16. 6% of the total electricity and 70% of all renewable electricity. Hydropower is produced in 150 countries, with the Asia-Pacific region generating 33 percent of global hydropower in 2013, China is the largest hydroelectricity producer, with 920 TWh of product

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The Three Gorges Dam in Central China is the world's largest power producing facilitiy of any kind.

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Museum Hydroelectric power plant ″Under the Town″ in Serbia, built in 1900.

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Turbine row at Los Nihuiles Power Station in Mendoza, Argentina

Nuclear power
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Nuclear power is the use of nuclear reactions that release nuclear energy to generate heat, which most frequently is then used in steam turbines to produce electricity in a nuclear power plant. The term includes nuclear fission, nuclear decay and nuclear fusion, since all electricity supplying technologies use cement, etc. during construction, emis

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The 1200 MWe, Leibstadt fission-electric power station in Switzerland. The boiling water reactor (BWR), located inside the dome capped cylindrical structure, is dwarfed in size by its cooling tower. The station produces a yearly average of 25 million kilowatt-hours per day, sufficient to power a city the size of Boston.

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The Palo Verde Nuclear Generating Station, the largest in the US with 3 pressurized water reactors (PWRs), is situated in the Arizona desert. It uses sewage from cities as its cooling water in 9 squat mechanical draft cooling towers. Its total spent fuel /"waste" inventory produced since 1986, is contained in dry cask storage cylinders located between the artificial body of water and the electrical switchyard.

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U.S. nuclear powered ships,(top to bottom) cruisers USS Bainbridge, the USS Long Beach and the USS Enterprise, the longest ever naval vessel, and the first nuclear-powered aircraft carrier. Picture taken in 1964 during a record setting voyage of 26,540 nmi (49,190 km) around the world in 65 days without refueling. Crew members are spelling out Einstein 's mass-energy equivalence formula E = mc 2 on the flight deck.

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The Russian nuclear-powered icebreaker NS Yamal on a joint scientific expedition with the NSF in 1994.

Solar power
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Solar power is the conversion of energy from sunlight into electricity, either directly using photovoltaics, or indirectly using concentrated solar power. Concentrated solar power systems use lenses or mirrors and tracking systems to focus a large area of sunlight into a small beam, Photovoltaic cells convert light into an electric current using th

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A solar PV array on a rooftop in Hong Kong

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The first three concentrated solar power (CSP) units of Spain's Solnova Solar Power Station in the foreground, with the PS10 and PS20 solar power towers in the background

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CPV modules on dual axis solar trackers in Golmud, China

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Ivanpah Solar Electric Generating System with all three towers under load during February 2014, with the Clark Mountain Range seen in the distance

Wind turbine
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A wind turbine is a device that converts the winds kinetic energy into electrical power. Wind turbines are manufactured in a range of vertical and horizontal axis types. The smallest turbines are used for such as battery charging for auxiliary power for boats or caravans or to power traffic warning signs. Slightly larger turbines can be used for ma

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Offshore wind farm, using 5 MW turbines REpower 5M in the North Sea off the coast of Belgium.

Commuter rail
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Trains operate following a schedule, at speeds varying from 50 to 200 km/h. Distance charges or zone pricing may be used and they primarily serve lower density suburban areas, and often share right-of-way with intercity or freight trains. Some services operate only during peak hours and others uses fewer departures during off peak hours, average sp

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The Long Island Rail Road operates electric and diesel service into New York City along with Metro-North Railroad and New Jersey Transit Rail.

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Mumbai Suburban Railway, the lifeline of Mumbai, carries more than 7.24 million commuters on a daily basis

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S-Bahns, like the one in Berlin, are not considered commuter rail.

4.
An electric multiple unit on the Gyeongchun Line operated by Korail in Seoul, South Korea

InterCityExpress
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The Intercity-Express or ICE is a system of high-speed trains predominantly running in Germany and its surrounding countries. It is the highest service category offered by DB Fernverkehr and is the flagship of Deutsche Bahn, the brand name ICE is among the best-known in Germany, with a brand awareness close to 100%, according to DB. There are curre

1.
A German ICE 3 trainset

2.
Intercity-Express

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InterCityExperimental (ICE V) first run as a full train, near Munich (Sept. 1985)

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ICE 1 on the Nuremberg-Ingolstadt line (Dec. 2006)

Acela
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The route contains segments of high-speed rail, and Acela Express trains are the fastest trainsets in the Americas, they attain 150 mph on 28 miles of the route. Acela trains use tilting technology, which helps control lateral centrifugal forces, over this route, Acela and the Northeast Regional line captured a 75% share of air/train commuters betw

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Amtrak Acela Express train, led by power car #2009, at Old Saybrook, Connecticut

2.
Acela Express

3.
Northbound Acela on the Northeast Corridor south of Philadelphia

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An Acela Regional train at South Station, Boston in 2002

Shinkansen
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The Shinkansen is a network of high-speed railway lines in Japan operated by five Japan Railways Group companies. The nickname bullet train is used in English for these high-speed trains. The maximum operating speed is 320 km/h, test runs have reached 443 km/h for conventional rail in 1996, and up to a world record 603 km/h for maglev trains in Apr

China Railway High-speed
–
China Railway High-speed is the high-speed rail service operated by China Railway. Hexie Hao is the designation for rolling stock operated for this service, All trains had been marked CRH, before being changed shortly afterwards to the Chinese characters 和谐号 on the centre of the head vehicles and the side of the walls of other vehicles. The introdu

TGV
–
TGV is Frances intercity high-speed rail service, operated by SNCF, the national rail operator. It was developed in the 1970s by GEC-Alsthom and SNCF, originally designed as turbotrains to be powered by gas turbines, the prototypes evolved into electric trains with the 1973 oil crisis. A TGV test train set the record for the fastest wheeled train,

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A TGV Sud-Est set in the original orange livery, since superseded by silver and blue

Regenerative braking
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A regenerative brake is an energy recovery mechanism which slows a vehicle or object by converting its kinetic energy into a form which can be either used immediately or stored until needed. This contrasts with conventional braking systems, where the kinetic energy is converted to unwanted and wasted heat by friction in the brakes. In addition to i

1.
Mechanism for regenerative brake on the roof of a Škoda Astra tram

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The S7/8 Stock on the London Underground can return 20% of its energy usage to the network

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A Tesla Model S P85+ using regenerative braking power in excess of 60 kW. During regenerative braking the power indicator is green

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The box extending sideways from the roof directly over the word "operation" allows air to freely flow through the resistors of the dynamic brakes on this diesel-electric locomotive.

Kinetic energy
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In physics, the kinetic energy of an object is the energy that it possesses due to its motion. It is defined as the work needed to accelerate a body of a mass from rest to its stated velocity. Having gained this energy during its acceleration, the body maintains this kinetic energy unless its speed changes, the same amount of work is done by the bo

1.
The cars of a roller coaster reach their maximum kinetic energy when at the bottom of their path. When they start rising, the kinetic energy begins to be converted to gravitational potential energy. The sum of kinetic and potential energy in the system remains constant, ignoring losses to friction.

Baltimore Belt Line
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It included the Howard Street Tunnel, the Mount Royal Station and the first mainline railroad electrification in the United States. The line is operated by CSX Transportation as part of its Baltimore Terminal Subdivision. In 1884, the PW&B was purchased by the Pennsylvania Railroad, a rival of the B&O. The B&O then proceeded to build its Philadelph

1.
B&O's overhead third-rail system at Guilford Avenue in Baltimore, 1901, part of the Baltimore Belt Line. The central position of the overhead conductors was dictated by the many tunnels on the line: the ∩ -shaped rails were located at the highest point in the roof to give the most clearance

2.
Mount Royal Station (in 1961)

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Howard Street Tunnel

4.
Baltimore & Ohio electric engine

Pantograph (rail)
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A pantograph is an apparatus mounted on the roof of an electric train, tram or electric bus to collect power through contact with an overhead catenary wire. It is a type of current collector. Typically, a wire is used, with the return current running through the track. The term stems from the resemblance of some styles to the mechanical pantographs

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The diamond-shaped, electric-rod pantograph of the Swiss cogwheel locomotive of the Schynige Platte railway in Schynige Platte, built in 1911

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The (asymmetrical) 'Z'-shaped pantograph of the electrical pickup on the Berlin Straßenbahn. This pantograph uses a single-arm design

3.
Close up of a single arm pantograph on a British Rail Class 333.

4.
High-performance pantograph used for measurements on the ICE S

Alco-GE
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Alco-GE was a partnership between the American Locomotive Company and General Electric that lasted from 1940 to 1953. Under this arrangement, Alco produced the body and prime mover. Alco management could see that the market for steam locomotives would soon vanish, notable locomotives produced by Alco-GE were the RS-1, the first road switcher, and U

2.
The RS-1 was a highly successful Alco-GE model.

3.
Subsidiaries and divisions

NYC S-Motor
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S-Motor was the class designation given by the New York Central to its ALCO-GE built S-1, S-2, S-2a and S-3 electric locomotives. The S-Motors hold the distinction of being the worlds first mass-produced main line locomotives with the prototype #6000 being constructed in 1904. The S-Motors would serve alone until the more powerful T-motors began to

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Prototype S-1 class #6000 (later #100)

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The original S-Motor, former No. 6000, awaiting restoration south of Albany, NY in 2012.

Milwaukee Road class ES-2
–
The Milwaukee Roads class ES-2 comprised four electric switcher locomotives. Two were built in 1916 and the two in 1919. They were of steeplecab design, with a single roof-mounted pantograph to access the Milwaukees 3,000 V DC overhead line, originally numbered 10050–10053, they were renumbered E80–E83 in March 1939. The ES-2 was the Milwaukee Road

1.
Milwaukee Road class ES-2

Steeplecab
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In railroad terminology, a steeplecab is a style or design of electric locomotive, the term is rarely if ever used for other forms of power. The name originated in North America and has used in Britain as well as the alternative camelback. A steeplecab design has a driving cab area which may include a full-height area in between for electrical equi

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A modern SBB Steeplecab electric shunter, SBB-CFF-FFS Ee 922.

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A GE steeplecab electric locomotive. This example is fitted with trolley poles for service on an interurban railroad.

3.
A Milwaukee Road class ES-2, an example of a larger steeplecab switcher for service on an electrified heavy-duty railroad.

Switcher
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They do this in classification yards. Switchers may also make short runs and even be the only motive power on branch lines and switching. The term can also be used to describe the workers operating these engines or engaged in directing shunting operations, the typical switcher is optimised for its job, being relatively low-powered but with a high s

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A modern US switcher, an EMD MP15DC

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British Rail Class 08 — a typical smaller European shunter

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A switcher once used on military premises

4.
Light dual-mode (electric and diesel) shunter SBB Tem 346

Aberdeen
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Nicknames include the Granite City, the Grey City and the Silver City with the Golden Sands. During the mid-18th to mid-20th centuries, Aberdeens buildings incorporated locally quarried grey granite, since the discovery of North Sea oil in the 1970s, other nicknames have been the Oil Capital of the World or the Energy Capital of the World. The area

1.
From the top: Part of the Aberdeen skyline, Aberdeen Harbour, and the High Street in Old Aberdeen.

4.
The Town House, Old Aberdeen. Once a separate burgh, Old Aberdeen was incorporated into the city in 1891

Galvanic cell
–
It generally consists of two different metals connected by a salt bridge, or individual half-cells separated by a porous membrane. Volta was the inventor of the pile, the first electrical battery. In common usage, the battery has come to include a single galvanic cell. In 1780, Luigi Galvani discovered that two different metals are connected and th

1.
Contents

Reluctance motor
–
A reluctance motor is a type of electric motor that induces non-permanent magnetic poles on the ferromagnetic rotor. The rotor does not have any windings, torque is generated through the phenomenon of magnetic reluctance. There are various types of motors, Synchronous reluctance Variable reluctance Switched reluctance Variable reluctance stepping.

Commutator (electric)
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It consists of a cylinder composed of multiple metal contact segments on the rotating armature of the machine. The windings on the armature are connected to the commutator segments, Commutators are used in direct current machines, dynamos and many DC motors as well as universal motors. In a motor the commutator applies electric current to the windi

Werner von Siemens
–
Ernst Werner Siemens was a German inventor and industrialist. Siemens’s name has been adopted as the SI unit of electrical conductance and he was also the founder of the electrical and telecommunications company Siemens. He was a brother of Carl Heinrich von Siemens and Carl Wilhelm Siemens, sons of Christian Ferdinand Siemens, after finishing scho

1.
Werner von Siemens

Berlin
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Berlin is the capital and the largest city of Germany as well as one of its constituent 16 states. With a population of approximately 3.5 million, Berlin is the second most populous city proper, due to its location in the European Plain, Berlin is influenced by a temperate seasonal climate. Around one-third of the area is composed of forests, parks

Gross-Lichterfelde Tramway
–
The Gross Lichterfelde Tramway was the worlds first electric tramway. It was built by the Siemens & Halske company in Lichterfelde, a suburb of Berlin, werner von Siemens had presented the first electric passenger train at the Berlin industrial exhibition two years before. The 2.4 km long line started at Berlin-Lichterfelde Ost station on the Anhal

1.
Lichterfelde tram, 1882

2.
A photo of a plaque raised in Lichterfelde, Berlin, Germany to mark the world's first electric street car. The plaque is located on a stand near the Lichterfede Ost Railway Station in Berlin, Germany.

Volk's Electric Railway
–
Volks Electric Railway is a narrow gauge heritage railway that runs along a length of the seafront of the English seaside resort of Brighton. It was built by Magnus Volk, the first section being completed in August 1883, although it was preceded by Werner von Siemenss 1879 demonstration line in Berlin and by the Gross-Lichterfelde Tramway of 1881,

1.
Aquarium Station

2.
Black Rock terminus in 1980

3.
Halfway station

Tram
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A tram is a rail vehicle which runs on tracks along public urban streets, and also sometimes on a segregated right of way. The lines or networks operated by tramcars are called tramways, Tramways powered by electricity, the most common type historically, were once called electric street railways. However, trams were used in urban areas before the u

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Trams in Vienna, one of the largest existing networks in the world

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The Welsh Swansea and Mumbles Railway ran the world's first passenger tram service

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Steam hauled tram in Italy c 1890s

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A San Francisco cable car: a cable pulled system, still operating as of 2015 [update]

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Postcard of electric trolley-powered streetcars in Richmond, Virginia, in 1923, two generations after Frank J. Sprague successfully demonstrated his new system on the hills in 1888. The intersection shown is at 8th & Broad Streets.

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Clockwise, from top: Midtown Manhattan, Times Square, the Unisphere in Queens, the Brooklyn Bridge, Lower Manhattan with One World Trade Center, Central Park, the headquarters of the United Nations, and the Statue of Liberty

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New Amsterdam, centered in the eventual Lower Manhattan, in 1664, the year England took control and renamed it "New York".

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The Battle of Long Island, the largest battle of the American Revolution, took place in Brooklyn in 1776.

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Broadway follows the Native American Wickquasgeck Trail through Manhattan.

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The combination of the Harlem River, Harlem River Ship Canal, and Spuyten Duyvil Creek, shown in red, form a single channel between the Bronx and Manhattan in New York City. Today, it's all considered the Harlem River.

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The Henry Hudson Bridge crosses the waterway at its west end.

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Blue shows the original path of the creek, north around Marble Hill and then curving south around the tip of the Bronx

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Aerial view of the northern part of Harlem River, with the larger Hudson River close by in the background

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Three-phase transformer with four wire output for 208Y/120 volt service: one wire for neutral, others for A, B and C phases

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Three-phase electric power transmission lines

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Left: Elementary six-wire three-phase alternator, with each phase using a separate pair of transmission wires. Right: Elementary three-wire three-phase alternator, showing how the phases can share only three wires.

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Collage of Frankfurt, clockwise from top of left to right: Facade of the Römer and Frankfurt Cathedral, statue of Charlemagne in Frankfurt Historical Museum, view of Frankfurt skyline and Main River

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An industrial type of AC motor with electrical terminal box at the top and output rotating shaft on the left. Such motors are widely used for pumps, blowers, conveyors and other industrial machinery.

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The Hungarian "ZBD" Team (Károly Zipernowsky, Ottó Bláthy, Miksa Déri). They were the inventors of the first high efficiency, closed core shunt connection Transformer. The three also invented the modern power distribution system: Instead of former series connection they connect transformers that supply the appliances in parallel to the main line. These inventions of ZBD-team put a stop to the War of Currents.

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Clockwise from top left: Chinese forces in the Battle of Wanjialing, Australian 25-pounder guns during the First Battle of El Alamein, German Stuka dive bombers on the Eastern Front in December 1943, a U.S. naval force in the Lingayen Gulf, Wilhelm Keitel signing the German Instrument of Surrender, Soviet troops in the Battle of Stalingrad

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The League of Nations assembly, held in Geneva, Switzerland, 1930

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Adolf Hitler at a German National Socialist political rally in Weimar, October 1930

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Italian soldiers recruited in 1935, on their way to fight the Second Italo-Abyssinian War

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Montage of New Haven. Clockwise from top left: Downtown New Haven skyline, East Rock Park, summer festivities on the New Haven Green, shops along Upper State Street, Five Mile Point Lighthouse, Harkness Tower, and Connecticut Hall at Yale.

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Seal

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The 1638 nine-square plan, with the extant New Haven Green at its center, continues to define New Haven's downtown

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From top to bottom, left to right: the Boston skyline viewed from the Bunker Hill Monument; the Museum of Fine Arts; Faneuil Hall; Massachusetts State House; The First Church of Christ, Scientist; Boston Public Library; the John F. Kennedy Presidential Library and Museum; South Station; Boston University and the Charles River; Arnold Arboretum; Fenway Park; and the Boston Common